# Consciousness Studies/Seventeenth And Eighteenth Century Philosophy

## Rene Descartes (1596-1650)

Descartes was also known as Cartesius. He had an empirical approach to
consciousness and the mind, describing in his *Meditations on First
Philosophy* (1641) what it is like to be human. His idea of perception
is summarised in the diagram below.

![](Constuddescart3.png "Constuddescart3.png")

### Dubitability

Descartes is probably most famous for his statement:

`<font face="times new roman">`{=html}\"But immediately upon this I
observed that, whilst I thus wished to think that all was false, it was
absolutely necessary that I, who thus thought, should be somewhat; and
as I observed that this truth, I think, therefore I am (COGITO ERGO
SUM), was so certain and of such evidence that no ground of doubt,
however extravagant, could be alleged by the sceptics capable of shaking
it, I concluded that I might, without scruple, accept it as the first
principle of the philosophy of which I was in search.\"`</font>`{=html}

Descartes is clear that what he means by *thought* is all the things
that occur in experience, whether dreams, sensations, symbols etc.:

`<font face="times new roman">`{=html}\"5. Of my thoughts some are, as
it were, images of things, and to these alone properly belongs the name
IDEA; as when I think \[ represent to my mind \] a man, a chimera, the
sky, an angel or God. Others, again, have certain other forms; as when I
will, fear, affirm, or deny, I always, indeed, apprehend something as
the object of my thought, but I also embrace in thought something more
than the representation of the object; and of this class of thoughts
some are called volitions or affections, and others judgments.\"
(Meditation III).`</font>`{=html}

He repeats this general description of thought in many places in the
Meditations and elsewhere. What Descartes is saying is that his
meditator has thoughts; that there are thoughts and this cannot be
doubted when and where they occur (Russell (1945) makes this clear).

Needless to say the basic *cogito* put forward by Descartes has provoked
endless debate, much of it based on the false premise that Descartes was
presenting an inference or argument rather than just saying that thought
certainly exists. However, the extent to which the philosopher can go
beyond this certainty to concepts such as God, science or the soul is
highly problematical.

### The description of thoughts and mind

!DescartesDescartes uses the words
\"ideas\" and \"imagination\" in a rather unusual fashion. The word
\"idea\" he defines as follows:

`<font face="times new roman">`{=html}\"5. Of my thoughts some are, as
it were, images of things, and to these alone properly belongs the name
IDEA; as when I think \[ represent to my mind \] a man, a chimera, the
sky, an angel or God.\" (Meditation III).`</font>`{=html}

As will be seen later, Descartes regards his mind as an unextended thing
(a point) so \"images of things\" or \"IDEAS\" require some way of being
extended. In the *Treatise on Man* (see below) he is explicit that ideas
are extended things in the brain, on the surface of the \"common
sense\". In *Rules for the Direction of the Mind* he notes that we
\"receive ideas from the common sensibility\", an extended part of the
brain. This usage of the term \"ideas\" is very strange to the modern
reader and the source of many mistaken interpretations. It should be
noted that occasionally Descartes uses the term \'idea\' according to
its usual meaning where it is almost interchangeable with \'thought\' in
general but usually he means a representation laid out in the brain.

Descartes considers the imagination to be the way that the mind \"turns
towards the body\" (by which Descartes means the part of the brain in
the body called the senses communis):

`<font face="times new roman">`{=html}\"3. I remark, besides, that this
power of imagination which I possess, in as far as it differs from the
power of conceiving, is in no way necessary to my \[nature or\] essence,
that is, to the essence of my mind; for although I did not possess it, I
should still remain the same that I now am, from which it seems we may
conclude that it depends on something different from the mind. And I
easily understand that, if some body exists, with which my mind is so
conjoined and united as to be able, as it were, to consider it when it
chooses, it may thus imagine corporeal objects; so that this mode of
thinking differs from pure intellection only in this respect, that the
mind in conceiving turns in some way upon itself, and considers some one
of the ideas it possesses within itself; but in imagining it turns
toward the body, and contemplates in it some object conformed to the
idea which it either of itself conceived or apprehended by sense.\"
Meditations VI `</font>`{=html}

So ideas, where they become imagined images of things were thought by
Descartes to involve a phase of creating a form in the brain.

Descartes gives a clear description of his experience as a container
that allows length, breadth, depth, continuity and time with contents
arranged within it:

`<font face="times new roman">`{=html}\"2. But before considering
whether such objects as I conceive exist without me, I must examine
their ideas in so far as these are to be found in my consciousness, and
discover which of them are distinct and which confused.`</font>`{=html}

`<font face="times new roman">`{=html}3. In the first place, I
distinctly imagine that quantity which the philosophers commonly call
continuous, or the extension in length, breadth, and depth that is in
this quantity, or rather in the object to which it is attributed.
Further, I can enumerate in it many diverse parts, and attribute to each
of these all sorts of sizes, figures, situations, and local motions;
and, in fine, I can assign to each of these motions all degrees of
duration.\"(Meditation V).`</font>`{=html}

He points out that sensation occurs by way of the brain, conceptualising
the brain as the place in the body where the extended experiences are
found : Meditations VI:

`<font face="times new roman">`{=html}\"20. I remark, in the next place,
that the mind does not immediately receive the impression from all the
parts of the body, but only from the brain, or perhaps even from one
small part of it, viz., that in which the common sense (senses communis)
is said to be, which as often as it is affected in the same way gives
rise to the same perception in the mind, although meanwhile the other
parts of the body may be diversely disposed, as is proved by innumerable
experiments, which it is unnecessary here to enumerate.\"
`</font>`{=html}

He finds that both imaginings and perceptions are extended things and
hence in the (brain part) of the body. The area of extended things is
called the *res extensa*, it includes the brain, body and world beyond.
He also considers the origin of intuitions, suggesting that they can
enter the mind without being consciously created: Meditations VI, 10 :

`<font face="times new roman">`{=html}\"10. Moreover, I find in myself
diverse faculties of thinking that have each their special mode: for
example, I find I possess the faculties of imagining and perceiving,
without which I can indeed clearly and distinctly conceive myself as
entire, but I cannot reciprocally conceive them without conceiving
myself, that is to say, without an intelligent substance in which they
reside, for \[in the notion we have of them, or to use the terms of the
schools\] in their formal concept, they comprise some sort of
intellection; whence I perceive that they are distinct from myself as
modes are from things. I remark likewise certain other faculties, as the
power of changing place, of assuming diverse figures, and the like, that
cannot be conceived and cannot therefore exist, any more than the
preceding, apart from a substance in which they inhere. It is very
evident, however, that these faculties, if they really exist, must
belong to some corporeal or extended substance, since in their clear and
distinct concept there is contained some sort of extension, but no
intellection at all. Further, I cannot doubt but that there is in me a
certain passive faculty of perception, that is, of receiving and taking
knowledge of the ideas of sensible things; but this would be useless to
me, if there did not also exist in me, or in some other thing, another
active faculty capable of forming and producing those ideas. But this
active faculty cannot be in me \[in as far as I am but a thinking
thing\], seeing that it does not presuppose thought, and also that those
ideas are frequently produced in my mind without my contributing to it
in any way, and even frequently contrary to my will. This faculty must
therefore exist in some substance different from me, in which all the
objective reality of the ideas that are produced by this faculty is
contained formally or eminently, as I before remarked; and this
substance is either a body, that is to say, a corporeal nature in which
is contained formally \[and in effect\] all that is objectively \[and by
representation\] in those ideas; or it is God himself, or some other
creature, of a rank superior to body, in which the same is contained
eminently. But as God is no deceiver, it is manifest that he does not of
himself and immediately communicate those ideas to me, nor even by the
intervention of any creature in which their objective reality is not
formally, but only eminently, contained. For as he has given me no
faculty whereby I can discover this to be the case, but, on the
contrary, a very strong inclination to believe that those ideas arise
from corporeal objects, I do not see how he could be vindicated from the
charge of deceit, if in truth they proceeded from any other source, or
were produced by other causes than corporeal things: and accordingly it
must be concluded, that corporeal objects exist. Nevertheless, they are
not perhaps exactly such as we perceive by the senses, for their
comprehension by the senses is, in many instances, very obscure and
confused; but it is at least necessary to admit that all which I clearly
and distinctly conceive as in them, that is, generally speaking all that
is comprehended in the object of speculative geometry, really exists
external to me. \"`</font>`{=html}

He considers that the mind itself is the thing that generates thoughts
and is not extended (occupies no space). This \'mind\' is known as the
*res cogitans*. The mind works on the imaginings and perceptions that
exist in that part of the body called the brain. This is Descartes\'
dualism: it is the proposition that there is an unextended place called
the mind that acts upon the extended things in the brain. Meditations
VI, 9:

`<font face="times new roman">`{=html}\"\... And although I may, or
rather, as I will shortly say, although I certainly do possess a body
with which I am very closely conjoined; nevertheless, because, on the
one hand, I have a clear and distinct idea of myself, in as far as I am
only a thinking and unextended thing, and as, on the other hand, I
possess a distinct idea of body, in as far as it is only an extended and
unthinking thing, it is certain that I, \[that is, my mind, by which I
am what I am\], is entirely and truly distinct from my body, and may
exist without it.\"`</font>`{=html}

Notice that the intellection associated with ideas is part of an
\"active faculty capable of forming and producing those ideas\" that has
a \"corporeal nature\" (it is in the brain). This suggests that the
\"thinking\" in the passage above applies only to those thoughts that
are unextended, however, it is difficult to find a definition of these
particular thoughts.

\"Rules for the Direction of the Mind\" demonstrates Descartes\'
dualism. He describes the brain as the part of the body that contains
images or phantasies of the world but believes that there is a further,
spiritual mind that processes the images in the brain:

`<font face="times new roman">`{=html}\"My fourth supposition is that
the power of movement, in fact the nerves, originate in the brain, where
the phantasy is seated; and that the phantasy moves them in various
ways, as the external sense `<organ>`{=html} moves the
`<organ of>`{=html} common sensibility, or as the whole pen is moved by
its tip. This illustration also shows how it is that the phantasy can
cause various movements in the nerves, although it has not images of
these formed in itself, but certain other images, of which these
movements are possible effects. For the pen as a whole does not move in
the same way as its tip; indeed, the greater part of the pen seems to go
along with an altogether different, contrary motion. This enables us to
understand how the movements of all other animals are accomplished,
although we suppose them to have no consciousness (rerum cognitio) but
only a bodily `<organ of>`{=html} phantasy; and furthermore, how it is
that in ourselves those operations are performed which occur without any
aid of reason.`</font>`{=html}

`<font face="times new roman">`{=html}My fifth and last supposition is
that the power of cognition properly so called is purely spiritual, and
is just as distinct from the body as a whole as blood is from bone or a
hand from an eye; and that it is a single power. Sometimes it receives
images from the common sensibility at the same time as the phantasy
does; sometimes it applies itself to the images preserved in memory;
sometimes it forms new images, and these so occupy the imagination that
often it is not able at the same time to receive ideas from the common
sensibility, or to pass them on to the locomotive power in the way that
the body left to itself -would. \"`</font>`{=html}

Descartes sums up his concept of a point soul seeing forms in the world
via forms in the sensus communis in *Passions of the Soul*, 35:

\"By this means the two images which are in the brain form but one upon
the gland, which, acting immediately upon the soul, causes it to see the
form in the mind\".

### Anatomical and physiological ideas

In his *Treatise on Man* Descartes summarises his ideas on how we
perceive and react to things as well as how consciousness is achieved
anatomically and physiologically. The \'Treatise\' was written at a time
when even galvanic electricity was unknown. The excerpt given below
covers Descartes\' analysis of perception and stimulus-response
processing.

![](Constuddescart1.png "Constuddescart1.png")

`<font face="times new roman">`{=html} \"Thus for example \[in Fig 1\],
if fire A is close to foot B, the tiny parts of this fire (which, as you
know, move about very rapidly) have the power also to move the area of
skin which they touch. In this way they pull the tiny fibre *cc* which
you see attached to it, and simultaneously open the entrance to the pore
*de*, located opposite the point where this fiber terminates - just as
when you pull one end of a string, you cause a bell hanging at the other
end to ring at the same time.`</font>`{=html}

`<font face="times new roman">`{=html}When the entrance to the pore or
small tube *de* is opened in this way, the animal spirits from cavity F
enter and are carried through it - some to muscles which serve to pull
the foot away from the fire, some to muscles which turn the eyes and
head to look at it, and some to muscles which make the hands move and
the whole body turn in order to protect it.`</font>`{=html}

`<font face="times new roman">`{=html}Now I maintain that when God
unites a rational soul to this machine (in a way that I intend to
explain later) he will place its principle seat in the brain, and will
make its nature such that the soul will have different sensations
corresponding to the different ways in which the entrances to the pores
in the internal surface of the brain are opened by means of
nerves.`</font>`{=html}

![](Constuddescart2.png "Constuddescart2.png")

`<font face="times new roman">`{=html}In order to see clearly how ideas
are formed of the objects which strike the senses, observe in this
diagram \[fig 2\] the tiny fibres 12, 34, 56, and the like, which make
up the optic nerve and stretch from the back of the eye at 1, 3, 5 to
the internal surface of the brain at 2, 4, 6. Now assume that these
fibres are so arranged that if the rays coming, for example, from point
A of the object happen to press upon the back of the eye at point 1,
they pull the whole of fibre 12 and enlarge the opening of the tiny tube
marked 2. In the same way, the rays which come from point B enlarge the
opening of the tiny tube 4, and likewise for the others. We have already
described how, depending on the different ways in which the points 1, 3,
5 are pressed by these rays, a figure is traced on the back of the eye
corresponding to that of the object ABC. Similarly it is obvious that,
depending on the different ways in which the tiny tubes 2, 4, 6 are
opened by the fibres 12, 34, 56 etc., a corresponding figure must also
be traced on the internal surface of the brain.`</font>`{=html}

\.....

`<font face="times new roman">`{=html}And note that by \'figures\' I
mean not only things which somehow represent the position of the edges
and surfaces of objects, but also anything which, as I said above, can
give the soul occasion to perceive movement, size, distance, colours,
sounds, smells and other such qualities. And I also include anything
that can make the soul feel pleasure, pain, hunger, thirst, joy, sadness
and other such passions.`</font>`{=html}

\...

`<font face="times new roman">`{=html}Now among these figures, it is not
those imprinted on the external sense organs, or on the internal surface
of the brain, which should be taken to be ideas - but only those which
are traced in the spirits on the surface of gland H (*where the seat of
the imagination and the \'common sense\' is located*). That is to say,
it is only the latter figures which should be taken to be the forms or
images which the rational soul united to this machine will consider
directly when it imagines some object or perceives it by the
senses.`</font>`{=html}

`<font face="times new roman">`{=html}And note that I say \'imagines or
perceives by the senses\'. For I wish to apply the term \'idea\'
generally to all impressions which the spirits can receive as they leave
gland H. These are to be attributed to the \'common\' sense when they
depend on the presence of objects; but they may also proceed from many
other causes (as I shall explain later), and they should then be
attributed to the imagination. \"`</font>`{=html}

The *common sense* is referred to by philosophers as the *senses
communis*. Descartes considered this to be the place where all the
sensations were bound together and proposed the pineal gland for this
role. This was in the days before the concept of \'dominance\' of parts
of the brain had been developed so Descartes reasoned that only a single
organ could host a bound representation.

Notice how Descartes is explicit about ideas being **traced in the
spirits on the surface of the gland**. Notice also how the rational soul
will consider forms on the common sense **directly**.

Descartes believed that animals are not conscious because, although he
thought they possessed the stimulus-response loop in the same way as
humans he believed that they do not possess a soul.

## John Locke (1632-1704)

Locke\'s most important philosophical work on the human mind was \"An
Essay Concerning Human Understanding\" written in 1689. His idea of
perception is summarised in the diagram below:

![](Constudlocke1.png "Constudlocke1.png")

Locke is an Indirect Realist, admitting of external objects but
describing these as represented within the mind. The objects themselves
are thought to have a form and properties that are the *archetype* of
the object and these give rise in the brain and mind to derived copies
called *ektypa*.

Like Descartes, he believes that people have souls that produce
thoughts. Locke considers that sensations make their way from the senses
to the brain where they are laid out for understanding as a \'view\':

`<font face="times new roman">`{=html}\"And if these organs, or the
nerves which are the conduits to convey them from without to their
audience in the brain,- the mind\'s presence-room (as I may so call it)-
are any of them so disordered as not to perform their functions, they
have no postern to be admitted by; no other way to bring themselves into
view, and be perceived by the understanding.\" (Chapter III,
1).`</font>`{=html}

He considers that what is sensed becomes a mental thing: Chapter IX: Of
Perception paragraph 1:

`<font face="times new roman">`{=html}\"This is certain, that whatever
alterations are made in the body, if they reach not the mind; whatever
impressions are made on the outward parts, if they are not taken notice
of within, there is no perception. Fire may burn our bodies with no
other effect than it does a billet, unless the motion be continued to
the brain, and there the sense of heat, or idea of pain, be produced in
the mind; wherein consists actual perception. \"`</font>`{=html}

!LockeLocke calls the contents of
consciousness \"ideas\" (cf: Descartes, Malebranche) and regards
sensation, imagination etc. as being similar or even alike. Chapter I:
Of Ideas in general, and their Original:

`<font face="times new roman">`{=html}\"1. Idea is the object of
thinking. Every man being conscious to himself that he thinks; and that
which his mind is applied about whilst thinking being the ideas that are
there, it is past doubt that men have in their minds several ideas,-
such as are those expressed by the words whiteness, hardness, sweetness,
thinking, motion, man, elephant, army, drunkenness, and others: it is in
the first place then to be inquired, How he comes by them?
`</font>`{=html}

`<font face="times new roman">`{=html}I know it is a received doctrine,
that men have native ideas, and original characters, stamped upon their
minds in their very first being. This opinion I have at large examined
already; and, I suppose what I have said in the foregoing Book will be
much more easily admitted, when I have shown whence the understanding
may get all the ideas it has; and by what ways and degrees they may come
into the mind;- for which I shall appeal to every one\'s own observation
and experience. `</font>`{=html}

`<font face="times new roman">`{=html}2. All ideas come from sensation
or reflection. Let us then suppose the mind to be, as we say, white
paper, void of all characters, without any ideas:- How comes it to be
furnished? Whence comes it by that vast store which the busy and
boundless fancy of man has painted on it with an almost endless variety?
Whence has it all the materials of reason and knowledge? To this I
answer, in one word, from EXPERIENCE. In that all our knowledge is
founded; and from that it ultimately derives itself. Our observation
employed either, about external sensible objects, or about the internal
operations of our minds perceived and reflected on by ourselves, is that
which supplies our understandings with all the materials of thinking.
These two are the fountains of knowledge, from whence all the ideas we
have, or can naturally have, do spring. `</font>`{=html}

`<font face="times new roman">`{=html}3. The objects of sensation one
source of ideas. First, our Senses, conversant about particular sensible
objects, do convey into the mind several distinct perceptions of things,
according to those various ways wherein those objects do affect them.
And thus we come by those ideas we have of yellow, white, heat, cold,
soft, hard, bitter, sweet, and all those which we call sensible
qualities; which when I say the senses convey into the mind, I mean,
they from external objects convey into the mind what produces there
those perceptions. This great source of most of the ideas we have,
depending wholly upon our senses, and derived by them to the
understanding, I call SENSATION.`</font>`{=html}

`<font face="times new roman">`{=html}4. The operations of our minds,
the other source of them. Secondly, the other fountain from which
experience furnisheth the understanding with ideas is,- the perception
of the operations of our own mind within us, as it is employed about the
ideas it has got;- which operations, when the soul comes to reflect on
and consider, do furnish the understanding with another set of ideas,
which could not be had from things without. And such are perception,
thinking, doubting, believing, reasoning, knowing, willing, and all the
different actings of our own minds;- which we being conscious of, and
observing in ourselves, do from these receive into our understandings as
distinct ideas as we do from bodies affecting our senses. This source of
ideas every man has wholly in himself; and though it be not sense, as
having nothing to do with external objects, yet it is very like it, and
might properly enough be called internal sense. But as I call the other
SENSATION, so I Call this REFLECTION, the ideas it affords being such
only as the mind gets by reflecting on its own operations within itself.
By reflection then, in the following part of this discourse, I would be
understood to mean, that notice which the mind takes of its own
operations, and the manner of them, by reason whereof there come to be
ideas of these operations in the understanding. These two, I say, viz.
external material things, as the objects of SENSATION, and the
operations of our own minds within, as the objects of REFLECTION, are to
me the only originals from whence all our ideas take their beginnings.
The term operations here I use in a large sense, as comprehending not
barely the actions of the mind about its ideas, but some sort of
passions arising sometimes from them, such as is the satisfaction or
uneasiness arising from any thought.`</font>`{=html}

`<font face="times new roman">`{=html}5. All our ideas are of the one or
the other of these. The understanding seems to me not to have the least
glimmering of any ideas which it doth not receive from one of these two.
External objects furnish the mind with the ideas of sensible qualities,
which are all those different perceptions they produce in us; and the
mind furnishes the understanding with ideas of its own operations.
\"`</font>`{=html}

He calls ideas that come directly from the senses *primary qualities*
and those that come from reflection upon these he calls *secondary
qualities*:

`<font face="times new roman">`{=html}\"9. Primary qualities of bodies.
Qualities thus considered in bodies are, First, such as are utterly
inseparable from the body, in what state soever it be; and such as in
all the alterations and changes it suffers, all the force can be used
upon it, it constantly keeps; and such as sense constantly finds in
every particle of matter which has bulk enough to be perceived; and the
mind finds inseparable from every particle of matter, though less than
to make itself singly be perceived by our senses: \...\...\.... These I
call original or primary qualities of body, which I think we may observe
to produce simple ideas in us, viz. solidity, extension, figure, motion
or rest, and number. 10. Secondary qualities of bodies. Secondly, such
qualities which in truth are nothing in the objects themselves but power
to produce various sensations in us by their primary qualities\.....\"
(Chapter VIII).`</font>`{=html}

He gives examples of secondary qualities:

`<font face="times new roman">`{=html}\"13. How secondary qualities
produce their ideas. After the same manner, that the ideas of these
original qualities are produced in us, we may conceive that the ideas of
secondary qualities are also produced, viz. by the operation of
insensible particles on our senses. \.....v.g. that a violet, by the
impulse of such insensible particles of matter, of peculiar figures and
bulks, and in different degrees and modifications of their motions,
causes the ideas of the blue colour, and sweet scent of that flower to
be produced in our minds. It being no more impossible to conceive that
God should annex such ideas to such motions, with which they have no
similitude, than that he should annex the idea of pain to the motion of
a piece of steel dividing our flesh, with which that idea hath no
resemblance.\" (Chapter VIII).`</font>`{=html}

He argues against all conscious experience being in mental space (does
not consider that taste might be on the tongue or a smell come from a
cheese): Chapter XIII: Complex Ideas of Simple Modes:- and First, of the
Simple Modes of the Idea of Space - paragraph 25:

`<font face="times new roman">`{=html}\"I shall not now argue with those
men, who take the measure and possibility of all being only from their
narrow and gross imaginations: but having here to do only with those who
conclude the essence of body to be extension, because they say they
cannot imagine any sensible quality of any body without extension,- I
shall desire them to consider, that, had they reflected on their ideas
of tastes and smells as much as on those of sight and touch; nay, had
they examined their ideas of hunger and thirst, and several other pains,
they would have found that they included in them no idea of extension at
all, which is but an affection of body, as well as the rest,
discoverable by our senses, which are scarce acute enough to look into
the pure essences of things.\"`</font>`{=html}

Locke understood the \"specious\" or extended present but conflates this
with longer periods of time: Chapter XIV. Idea of Duration and its
Simple Modes - paragraph 1:

`<font face="times new roman">`{=html}\"Duration is fleeting extension.
There is another sort of distance, or length, the idea whereof we get
not from the permanent parts of space, but from the fleeting and
perpetually perishing parts of succession. This we call duration; the
simple modes whereof are any different lengths of it whereof we have
distinct ideas, as hours, days, years, &c., time and eternity.\"
`</font>`{=html}

Locke is uncertain about whether extended ideas are viewed from an
unextended soul.

`<font face="times new roman">`{=html}\"He that considers how hardly
sensation is, in our thoughts, reconcilable to extended matter; or
existence to anything that has no extension at all, will confess that he
is very far from certainly knowing what his soul is. It is a point which
seems to me to be put out of the reach of our knowledge: and he who will
give himself leave to consider freely, and look into the dark and
intricate part of each hypothesis, will scarce find his reason able to
determine him fixedly for or against the soul\'s materiality. Since, on
which side soever he views it, either as an unextended substance, or as
a thinking extended matter, the difficulty to conceive either will,
whilst either alone is in his thoughts, still drive him to the contrary
side.\"(Chapter III, 6).`</font>`{=html}

## David Hume (1711-1776)

**Hume (1739--40). A Treatise of Human Nature: Being An Attempt to
Introduce the Experimental Method of Reasoning Into Moral Subjects.**

!HumeHume represents a type of pure empiricism
where certainty is only assigned to present experience. As we can only
directly know the mind he works within this constraint. He admits that
there can be consistent bodies of knowledge within experience and would
probably regard himself as an Indirect Realist but with the caveat that
the things that are inferred to be outside the mind, in the physical
world, could be no more than inferences within the mind.

Hume has a clear concept of mental space and time that is informed by
the senses:

`<font face="times new roman">`{=html}\"The idea of space is convey\'d
to the mind by two senses, the sight and touch; nor does anything ever
appear extended, that is not either visible or tangible. That compound
impression, which represents extension, consists of several lesser
impressions, that are indivisible to the eye or feeling, and may be
call\'d impressions of atoms or corpuscles endow\'d with colour and
solidity. But this is not all. \'Tis not only requisite, that these
atoms shou\'d be colour\'d or tangible, in order to discover themselves
to our senses; \'tis also necessary we shou\'d preserve the idea of
their colour or tangibility in order to comprehend them by our
imagination. There is nothing but the idea of their colour or
tangibility, which can render them conceivable by the mind. Upon the
removal of the ideas of these sensible qualities, they are utterly
annihilated to the thought or imagination.\'`</font>`{=html}

`<font face="times new roman">`{=html}Now such as the parts are, such is
the whole. If a point be not consider\'d as colour\'d or tangible, it
can convey to us no idea; and consequently the idea of extension, which
is compos\'d of the ideas of these points, can never possibly exist. But
if the idea of extension really can exist, as we are conscious it does,
its parts must also exist; and in order to that, must be consider\'d as
colour\'d or tangible. We have therefore no idea of space or extension,
but when we regard it as an object either of our sight or
feeling.`</font>`{=html}

`<font face="times new roman">`{=html}The same reasoning will prove,
that the indivisible moments of time must be fill\'d with some real
object or existence, whose succession forms the duration, and makes it
be conceivable by the mind.\"`</font>`{=html}

In common with Locke and Eastern Philosophy, Hume considers reflection
and sensation to be similar, perhaps identical:

`<font face="times new roman">`{=html}\"Thus it appears, that the belief
or assent, which always attends the memory and senses, is nothing but
the vivacity of those perceptions they present; and that this alone
distinguishes them from the imagination. To believe is in this case to
feel an immediate impression of the senses, or a repetition of that
impression in the memory. \'Tis merely the force and liveliness of the
perception, which constitutes the first act of the judgment, and lays
the foundation of that reasoning, which we build upon it, when we trace
the relation of cause and effect.\"`</font>`{=html}

Hume considers that the origin of sensation can never be known,
believing that the canvass of the mind contains our view of the world
whatever the ultimate source of the images within the view and that we
can construct consistent bodies of knowledge within these constraints:

`<font face="times new roman">`{=html}\"As to those impressions, which
arise from the senses, their ultimate cause is, in my opinion, perfectly
inexplicable by human reason, and \'twill always be impossible to decide
with certainty, whether they arise immediately from the object, or are
produc\'d by the creative power of the mind, or are deriv\'d from the
author of our being. Nor is such a question any way material to our
present purpose. We may draw inferences from the coherence of our
perceptions, whether they be true or false; whether they represent
nature justly, or be mere illusions of the senses.\"`</font>`{=html}

It may be possible to trace the origins of Jackson\'s Knowledge Argument
in Hume\'s work:

`<font face="times new roman">`{=html}\" Suppose therefore a person to
have enjoyed his sight for thirty years, and to have become perfectly
well acquainted with colours of all kinds, excepting one particular
shade of blue, for instance, which it never has been his fortune to meet
with. Let all the different shades of that colour, except that single
one, be plac\'d before him, descending gradually from the deepest to the
lightest; \'tis plain, that he will perceive a blank, where that shade
is wanting, said will be sensible, that there is a greater distance in
that place betwixt the contiguous colours, than in any other. Now I ask,
whether \'tis possible for him, from his own imagination, to supply this
deficiency, and raise up to himself the idea of that particular shade,
tho\' it had never been conveyed to him by his senses? I believe i here
are few but will be of opinion that he can; and this may serve as a
proof, that the simple ideas are not always derived from the
correspondent impressions; tho\' the instance is so particular and
singular, that \'tis scarce worth our observing, and does not merit that
for it alone we should alter our general maxim.\"`</font>`{=html}

**David Hume (1748) An Enquiry Concerning Human Understanding**

Hume\'s view of Locke and Malebranche:

`<font face="times new roman">`{=html}\"The fame of Cicero flourishes at
present; but that of Aristotle is utterly decayed. La Bruyere passes the
seas, and still maintains his reputation: But the glory of Malebranche
is confined to his own nation, and to his own age. And Addison, perhaps,
will be read with pleasure, when Locke shall be entirely
forgotten.\"`</font>`{=html}

He is clear about relational knowledge in space and time:

`<font face="times new roman">`{=html}\"13. .. But though our thought
seems to possess this unbounded liberty, we shall find, upon a nearer
examination, that it is really confined within very narrow limits, and
that all this creative power of the mind amounts to no more than the
faculty of compounding, transposing, augmenting, or diminishing the
materials afforded us by the senses and experience. When we think of a
golden mountain, we only join two consistent ideas, gold, and mountain,
with which we were formerly acquainted.\"`</font>`{=html}

\...

`<font face="times new roman">`{=html}19. Though it be too obvious to
escape observation, that different ideas are connected together; I do
not find that any philosopher has attempted to enumerate or class all
the principles of association; a subject, however, that seems worthy of
curiosity. To me, there appear to be only three principles of connexion
among ideas, namely, Resemblance, Contiguity in time or place, and Cause
or Effect.\"`</font>`{=html}

He is also clear that, although we experience the output of processes,
we do not experience the processes themselves:

`<font face="times new roman">`{=html}\"29. It must certainly be
allowed, that nature has kept us at a great distance from all her
secrets, and has afforded us only the knowledge of a few superficial
qualities of objects; while she conceals from us those powers and
principles on which the influence of those objects entirely depends. Our
senses inform us of the colour, weight, and consistence of bread; but
neither sense nor reason can ever inform us of those qualities which fit
it for the nourishment and support of a human body. Sight or feeling
conveys an idea of the actual motion of bodies; but as to that wonderful
force or power, which would carry on a moving body for ever in a
continued change of place, and which bodies never lose but by
communicating it to others; of this we cannot form the most distant
conception. ..`</font>`{=html}

`<font face="times new roman">`{=html}58. \... All events seem entirely
loose and separate. One event follows another; but we never can observe
any tie between them. They seem conjoined, but never connected. And as
we can have no idea of any thing which never appeared to our outward
sense or inward sentiment, the necessary conclusion seems to be that we
have no idea of connexion or power at all, and that these words are
absolutely without any meaning, when employed either in philosophical
reasonings or common life. \"`</font>`{=html}

Our idea of process is not a direct experience but seems to originate
from remembering the repetition of events:

`<font face="times new roman">`{=html}\"59 ..It appears, then, that this
idea of a necessary connexion among events arises from a number of
similar instances which occur of the constant conjunction of these
events; nor can that idea ever be suggested by any one of these
instances, surveyed in all possible lights and positions. But there is
nothing in a number of instances, different from every single instance,
which is supposed to be exactly similar; except only, that after a
repetition of similar instances, the mind is carried by habit, upon the
appearance of one event, to expect its usual attendant, and to believe
that it will exist.\"`</font>`{=html}

## Emmanuel Kant (1724-1804)

!kantKant\'s greatest work on the subject
of consciousness and the mind is Critique of Pure Reason (1781). Kant
describes his objective in this work as discovering the axioms (\"a
priori concepts\") and then the processes of \'understanding\'.

`<font face="times new roman">`{=html}P12 \"This enquiry, which is
somewhat deeply grounded, has two sides. The one refers to the objects
of pure understanding, and is intended to expound and render
intelligible the objective validity of its a priori concepts. It is
therefore essential to my purposes. The other seeks to investigate the
pure understanding itself, its possibility and the cognitive faculties
upon which it rests; and so deals with it in its subjective aspect.
Although this latter exposition is of great importance for my chief
purpose, it does not form an essential part of it. For the chief
question is always simply this: - what and how much can the
understanding and reason know apart from all
experience?\"`</font>`{=html}

Kant\'s idea of perception and mind is summarised in the illustration
below:

![](Constudkant.png "Constudkant.png")

\'Experience\' is simply accepted. Kant believes that the physical world
exists but is not known directly:

`<font face="times new roman">`{=html}P 24 \"For we are brought to the
conclusion that we can never transcend the limits of possible
experience, though that is precisely what this science is concerned,
above all else, to achieve. This situation yields, however, just the
very experiment by which, indirectly, we are enabled to prove the truth
of this first estimate of our a priori knowledge of reason, namely, that
such knowledge has to do only with appearances, and must leave the thing
in itself as indeed real per se, but as not known by us.
\"`</font>`{=html}

Kant is clear about the form and content of conscious experience. He
notes that we can only experience things that have appearance and
\'form\' - content and geometrical arrangement.

`<font face="times new roman">`{=html}P65-66 \"IN whatever manner and by
whatever means a mode of knowledge may relate to objects, intuition is
that through which it is in immediate relation to them, and to which all
thought as a means is directed. But intuition takes place only in so far
as the object is given to us. This again is only possible, to man at
least, in so far as the mind is affected in a certain way. The capacity
(receptivity) for receiving representations through the mode in which we
are affected by objects, is entitled sensibility. Objects are given to
us by means of sensibility, and it alone yields us intuitions; they are
thought through the understanding, and from the understanding arise
concepts. But all thought must, directly or indirectly, by way of
certain characters relate ultimately to intuitions, and therefore, with
us, to sensibility, because in no other way can an object be given to
us. The effect of an object upon the faculty of representation, so far
as we are affected by it, is sensation. That intuition which is in
relation to the object through sensation, is entitled empirical. The
undetermined object of an empirical intuition is entitled appearance.
That in the appearance which corresponds to sensation I term its matter;
but that which so determines the manifold of appearance that it allows
of being ordered in certain relations, I term the form of appearance.
That in which alone the sensations can be posited and ordered in a
certain form, cannot itself be sensation; and therefore, while the
matter of all appearance is given to us a posteriori only, its form must
lie ready for the sensations a priori in the mind, and so must allow of
being considered apart from all sensation. \"`</font>`{=html}

Furthermore he realises that experience exists without much content.
That consciousness depends on form:

`<font face="times new roman">`{=html}P66 \"The pure form of sensible
intuitions in general, in which all the manifold of intuition is
intuited in certain relations, must be found in the mind a priori. This
pure form of sensibility may also itself be called pure intuition. Thus,
if I take away from the representation of a body that which the
understanding thinks in regard to it, substance, force, divisibility,
etc. , and likewise what belongs to sensation, impenetrability,
hardness, colour, etc. , something still remains over from this
empirical intuition, namely, extension and figure. These belong to pure
intuition, which, even without any actual object of the senses or of
sensation, exists in the mind a priori as a mere form of sensibility.
The science of all principles of a priori sensibility I call
transcendental aesthetic.\"`</font>`{=html}

Kant proposes that space exists in our experience and that experience
could not exist without it (apodeictic means \'incontrovertible):

`<font face="times new roman">`{=html}P 68 \"1. Space is not an
empirical concept which has been derived from outer experiences. For in
order that certain sensations be referred to something outside me (that
is, to something in another region of space from that in which I find
myself), and similarly in order that I may be able to represent them as
outside and alongside one another, and accordingly as not only different
but as in different places, the representation of space must be
presupposed. The representation of space cannot, therefore, be
empirically obtained from the relations of outer appearance. On the
contrary, this outer experience is itself possible at all only through
that representation. 2. Space is a necessary a priori representation,
which underlies all outer intuitions. We can never represent to
ourselves the absence of space, though we can quite well think it as
empty of objects. It must therefore be regarded as the condition of the
possibility of appearances, and not as a determina- tion dependent upon
them. It is an a priori representation, which necessarily underlies
outer appearances. \* 3. The apodeictic certainty of all geometrical
propositions and the possibility of their a priori construction is
grounded in this a priori necessity of space.
\...\...\...\"`</font>`{=html}

He is equally clear about the necessity of time as part of experience
but he has no clear exposition of the (specious present) extended
present:

`<font face="times new roman">`{=html}P 74 \"1. Time is not an empirical
concept that has been derived from any experience. For neither
coexistence nor succession would ever come within our perception, if the
representation of time were not presupposed as underlying them a priori.
Only on the presupposition of time can we represent to ourselves a
number of things as existing at one and the same time (simultaneously)
or at different times (successively). They are connected with the
appearances only as effects accidentally added by the particular
constitution of the sense organs. Accordingly, they are not a priori
representations, but are grounded in sensation, and, indeed, in the case
of taste, even upon feeling (pleasure and pain), as an effect of
sensation. Further, no one can have a priori a representation of a
colour or of any taste; whereas, since space concerns only the pure form
of intuition, and therefore involves no sensation whatsoever, and
nothing empirical, all kinds and determinations of space can and must be
represented a priori, if concepts of figures and of their relations are
to arise. Through space alone is it possible that things should be outer
objects to us. ..2. 3.. 4.. 5\...\"`</font>`{=html}

Kant has a model of experience as a succession of 3D instants, based on
conventional 18th century thinking, allowing his reason to overcome his
observation. He says of time that:

`<font face="times new roman">`{=html}P 79 \" It is nothing but the form
of our inner intuition. If we take away from our inner intuition the
peculiar condition of our sensibility, the concept of time likewise
vanishes; it does not inhere in the objects, but merely in the subject
which intuits them. I can indeed say that my representations follow one
another; but this is only to say that we are conscious of them as in a
time sequence, that is, in conformity with the form of inner sense. Time
is not, therefore, something in itself, nor is it an objective
determination inherent in things.\"`</font>`{=html}

This analysis is strange because if uses the geometric term \"form\" but
then uses the processing term \"succession\".

## Gottfried Wilhelm Leibniz (1646-1716)

!LeibnizLeibniz is one of
the first to notice that there is a problem with the proposition that
computational machines could be conscious:

`<font face="times new roman">`{=html}\"One is obliged to admit that
perception and what depends upon it is inexplicable on mechanical
principles, that is, by figures and motions. In imagining that there is
a machine whose construction would enable it to think, to sense, and to
have perception, one could conceive it enlarged while retaining the same
proportions, so that one could enter into it, just like into a windmill.
Supposing this, one should, when visiting within it, find only parts
pushing one another, and never anything by which to explain a
perception. Thus it is in the simple substance, and not in the composite
or in the machine, that one must look for perception.\" Monadology,
17.`</font>`{=html}

Leibniz considered that the world was composed of \"monads\":

`<font face="times new roman">`{=html}\"1. The Monad, of which we shall
here speak, is nothing but a simple substance, which enters into
compounds. By \'simple\' is meant \'without parts.\' (Theod. 10.)
`</font>`{=html}

`<font face="times new roman">`{=html}2. And there must be simple
substances, since there are compounds; for a compound is nothing but a
collection or aggregatum of simple things.`</font>`{=html}

`<font face="times new roman">`{=html}3. Now where there are no parts,
there can be neither extension nor form \[figure\] nor divisibility.
These Monads are the real atoms of nature and, in a word, the elements
of things. \" (Monadology 1714).`</font>`{=html}

These monads are considered to be capable of perception through the
meeting of things at a point:

`<font face="times new roman">`{=html}\"They cannot have shapes, because
then they would have parts; and therefore one monad in itself, and at a
moment, cannot be distinguished from another except by its internal
qualities and actions; which can only be its *perceptions* (that is, the
representations of the composite, or of what is external, in the
simple), or its *appetitions* (its tending to move from one perception
to another, that is), which are the principles of change. For the
simplicity of a substance does not in any way rule out a multiplicity in
the modifications which must exist together in one simple substance; and
those modifications must consist in the variety of its relationships to
things outside it - like the way in which in a *centre*, or a *point*,
although it is completely simple, there are an infinity of angles formed
which meet in it.\" (Principles of Nature and Grace
1714).`</font>`{=html}

Leibniz also describes this in his \"New System\":

`<font face="times new roman">`{=html}\"It is only atoms of substance,
that is to say real unities absolutely devoid of parts, that can be the
sources of actions, and the absolute first principles of the composition
of things, and as it were the ultimate elements in the analysis of
substances `<substantial things>`{=html}. They might be called
*metaphysical points*; they have *something of the nature of life* and a
kind of *perception*, and *mathematical points* are their *point of
view* for expressing the universe.\"(New System (11)
1695).`</font>`{=html}

Having identified perception with metaphysical points Leibniz realises
that there is a problem connecting the points with the world (cf:
epiphenomenalism):

`<font face="times new roman">`{=html}\"Having decided these things, I
thought I had reached port, but when I set myself to think about the
union of the soul with the body I was as it were carried back into the
open sea. For I could find no way of explaining how the body can make
something pass over into the soul or vice versa, or how one created
substance can communicate with another.\"(New System (12)
1695).`</font>`{=html}

Leibniz devises a theory of \"pre-established harmony\" to overcome this
epiphenomenalism. He discusses how two separate clocks could come to
tell the same time and proposes that this could be due to mutual
influence of one clock on the other (\"the way of influence\"),
continual adjustment by a workman (\"the way of assistance\") or by
making the clocks so well that they are always in agreement (\"the way
of pre-established agreement\" or harmony). He considers each of these
alternatives for harmonising the perceptions with the world and
concludes that only the third is viable:

`<font face="times new roman">`{=html}\"Thus there remains only my
theory, *the way of pre-established harmony*, set up by a contrivance of
divine foreknowledge, which formed each of these substances from the
outset in so perfect, so regular, and so exact a manner, that merely by
following out its own laws, which were given to it when it was brought
into being, each substance is nevertheless in harmony with the other,
just as if there were a mutual influence between them, or as if in
addition to his general concurrence God were continually operating upon
them. (Third Explanation of the New System (5), 1696).\"`</font>`{=html}

This means that he must explain how perceptions involving the world take
place:

`<font face="times new roman">`{=html}\"Because of the plenitude of the
world everything is linked, and every body acts to a greater or lesser
extent on every other body in proportion to distance, and is affected by
it in return. It therefore follows that every monad is a living mirror,
or a mirror endowed with internal activity, representing the universe in
accordance with its own point of view, and as orderly as the universe
itself. The perceptions of monads arise one out of another by the laws
of appetite, or of the *final causes of good and evil* (which are
prominent perceptions, orderly or disorderly), just as changes in bodies
or in external phenomena arise one from another by the laws of
*efficient causes*, of motion that is. Thus there is perfect *harmony*
between the perceptions of the monad and the motions of bodies,
pre-established from the outset, between the system of efficient causes
and that of final causes. And it is that harmony that the agreement or
physical union between the soul and body consists, without either of
them being able to change the laws of the other.\" (Principles of Nature
and Grace (3) 1714).`</font>`{=html}

The \"laws of appetite\" are defined as:

`<font face="times new roman">`{=html}\"The action of the internal
principle which brings about change, or the passage from one perception
to another, can be called *appetition*. In fact appetite cannot always
attain in its entirety the whole of the perception towards which it
tends, but it always obtains some part of it, and attains new
perceptions. Monadology 15.`</font>`{=html}

Leibniz thought animals had souls but not minds:

`<font face="times new roman">`{=html}\"But *true* reasoning depends on
necessary or eternal truths like those of logic, numbers, and geometry,
which make indubitable connections between ideas, and conclusions which
are inevitable. Animals in which such conclusions are never perceived
are called *brutes*; but those which recognise such necessary truths are
what are rightly called *rational animals* and their souls are called
*minds*. (Principles of Nature and Grace (5) 1714).`</font>`{=html}

Minds allow reflection and awareness:

`<font face="times new roman">`{=html}\"And it is by the knowledge of
necessary truths, and by the abstractions they involve, that we are
raised to *acts of reflection*, which make us aware of what we call
*myself*, and make us think of this or that thing as in *ourselves*. And
in this way, by thinking of ourselves, we think of being, of substance,
of simples and composites, of the immaterial - and, by realising that
what is limited in us is limitless in him, of God himself. And so these
*acts of reflection* provide the principle objects of our reasonings.\"
Monadology, 30.`</font>`{=html}

## George Berkeley (1685 - 1753)

A Treatise on the Principles of Human Knowledge. 1710

!BerkeleyBerkeley
introduces the Principles of Human Knowledge with a diatribe against
abstract ideas. He uses the abstract ideas of animals as an example:

`<font face="times new roman">`{=html}\"Introduction. 9\...\.....The
constituent parts of the abstract idea of animal are body, life, sense,
and spontaneous motion. By body is meant body without any particular
shape or figure, there being no one shape or figure common to all
animals, without covering, either of hair, or feathers, or scales, &c.,
nor yet naked: hair, feathers, scales, and nakedness being the
distinguishing properties of particular animals, and for that reason
left out of the abstract idea. Upon the same account the spontaneous
motion must be neither walking, nor flying, nor creeping; it is
nevertheless a motion, but what that motion is it is not easy to
conceive. `</font>`{=html}

He then declares that such abstractions cannot be imagined. He
emphasises that ideas are \"represented to myself\" and have shape and
colour:

`<font face="times new roman">`{=html}\"Introduction. 10. Whether others
have this wonderful faculty of abstracting their ideas, they best can
tell: for myself, I find indeed I have a faculty of imagining, or
representing to myself, the ideas of those particular things I have
perceived, and of variously compounding and dividing them. I can imagine
a man with two heads, or the upper parts of a man joined to the body of
a horse. I can consider the hand, the eye, the nose, each by itself
abstracted or separated from the rest of the body. But then whatever
hand or eye I imagine, it must have some particular shape and colour.
Likewise the idea of man that I frame to myself must be either of a
white, or a black, or a tawny, a straight, or a crooked, a tall, or a
low, or a middle-sized man. I cannot by any effort of thought conceive
the abstract idea above described. And it is equally impossible for me
to form the abstract idea of motion distinct from the body moving, and
which is neither swift nor slow, curvilinear nor rectilinear; and the
like may be said of all other abstract general ideas
whatsoever.\"`</font>`{=html}

This concept of ideas as extended things, or representations, is typical
of the usage amongst philosophers in the 17th and 18th century and can
cause confusion in modern readers. Berkeley considers that words that
are used to describe classes of things in the abstract can only be
conceived as particular cases:

`<font face="times new roman">`{=html}\"Introduction. 15\... Thus, when
I demonstrate any proposition concerning triangles, it is to be supposed
that I have in view the universal idea of a triangle; which ought not to
be understood as if I could frame an idea of a triangle which was
neither equilateral, nor scalenon, nor equicrural; but only that the
particular triangle I consider, whether of this or that sort it matters
not, doth equally stand for and represent all rectilinear triangles
whatsoever, and is in that sense universal. All which seems very plain
and not to include any difficulty in it.`</font>`{=html}

Intriguingly, he considers that language is used to directly excite
emotions as well as to communicate ideas:

`<font face="times new roman">`{=html}\"Introduction. 20. \... I entreat
the reader to reflect with himself, and see if it doth not often happen,
either in hearing or reading a discourse, that the passions of fear,
love, hatred, admiration, disdain, and the like, arise immediately in
his mind upon the perception of certain words, without any ideas coming
between.`</font>`{=html}

Berkeley considers that extension is a quality of mind:

`<font face="times new roman">`{=html}\"11. Again, great and small,
swift and slow, are allowed to exist nowhere without the mind, being
entirely relative, and changing as the frame or position of the organs
of sense varies. The extension therefore which exists without the mind
is neither great nor small, the motion neither swift nor slow, that is,
they are nothing at all. But, say you, they are extension in general,
and motion in general: thus we see how much the tenet of extended
movable substances existing without the mind depends on the strange
doctrine of abstract ideas.\" `</font>`{=html}

He notes that the rate at which things pass may be related to the mind:

`<font face="times new roman">`{=html}\"14\..... Is it not as reasonable
to say that motion is not without the mind, since if the succession of
ideas in the mind become swifter, the motion, it is acknowledged, shall
appear slower without any alteration in any external object?
`</font>`{=html}

Berkeley raises the issue of whether objects exist without being
perceived. He bases his argument on the concept of perception being the
perceiving of \"our own ideas or sensations\":

`<font face="times new roman">`{=html}\"4. It is indeed an opinion
strangely prevailing amongst men, that houses, mountains, rivers, and in
a word all sensible objects, have an existence, natural or real,
distinct from their being perceived by the understanding. But, with how
great an assurance and acquiescence soever this principle may be
entertained in the world, yet whoever shall find in his heart to call it
in question may, if I mistake not, perceive it to involve a manifest
contradiction. For, what are the fore-mentioned objects but the things
we perceive by sense? and what do we perceive besides our own ideas or
sensations? and is it not plainly repugnant that any one of these, or
any combination of them, should exist unperceived?\"`</font>`{=html}

He further explains this concept in terms of some Eternal Spirit
allowing continued existence. Berkeley is clear that the contents of the
mind have \"colour, figure, motion, smell, taste etc.\":

`<font face="times new roman">`{=html}\"7. From what has been said it
follows there is not any other Substance than Spirit, or that which
perceives. But, for the fuller proof of this point, let it be considered
the sensible qualities are colour, figure, motion, smell, taste, etc.,
i.e. the ideas perceived by sense. Now, for an idea to exist in an
unperceiving thing is a manifest contradiction, for to have an idea is
all one as to perceive; that therefore wherein colour, figure, and the
like qualities exist must perceive them; hence it is clear there can be
no unthinking substance or substratum of those ideas.\"`</font>`{=html}

He elaborates the concept that there is no unthinking substance or
substratum for ideas and all is mind:

`<font face="times new roman">`{=html}\"18. But, though it were possible
that solid, figured, movable substances may exist without the mind,
corresponding to the ideas we have of bodies, yet how is it possible for
us to know this? Either we must know it by sense or by reason. As for
our senses, by them we have the knowledge only of our sensations, ideas,
or those things that are immediately perceived by sense, call them what
you will: but they do not inform us that things exist without the mind,
or unperceived, like to those which are perceived. This the materialists
themselves acknowledge. It remains therefore that if we have any
knowledge at all of external things, it must be by reason, inferring
their existence from what is immediately perceived by sense. But what
reason can induce us to believe the existence of bodies without the
mind, from what we perceive, since the very patrons of Matter themselves
do not pretend there is any necessary connexion betwixt them and our
ideas? I say it is granted on all hands (and what happens in dreams,
phrensies, and the like, puts it beyond dispute) that it is possible we
might be affected with all the ideas we have now, though there were no
bodies existing without resembling them. Hence, it is evident the
supposition of external bodies is not necessary for the producing our
ideas; since it is granted they are produced sometimes, and might
possibly be produced always in the same order, we see them in at
present, without their concurrence. \"`</font>`{=html}

and stresses that there is no apparent connection between mind and the
proposed material substrate of ideas:

`<font face="times new roman">`{=html}\"19. But, though we might
possibly have all our sensations without them, yet perhaps it may be
thought easier to conceive and explain the manner of their production,
by supposing external bodies in their likeness rather than otherwise;
and so it might be at least probable there are such things as bodies
that excite their ideas in our minds. But neither can this be said; for,
though we give the materialists their external bodies, they by their own
confession are never the nearer knowing how our ideas are produced;
since they own themselves unable to comprehend in what manner body can
act upon spirit, or how it is possible it should imprint any idea in the
mind. \..... `</font>`{=html}

Berkeley makes a crucial observation, that had also been noticed by
Descartes, that ideas are passive:

`<font face="times new roman">`{=html}\"25. All our ideas, sensations,
notions, or the things which we perceive, by whatsoever names they may
be distinguished, are visibly inactive- there is nothing of power or
agency included in them. So that one idea or object of thought cannot
produce or make any alteration in another. To be satisfied of the truth
of this, there is nothing else requisite but a bare observation of our
ideas. For, since they and every part of them exist only in the mind, it
follows that there is nothing in them but what is perceived: but whoever
shall attend to his ideas, whether of sense or reflexion, will not
perceive in them any power or activity; there is, therefore, no such
thing contained in them. A little attention will discover to us that the
very being of an idea implies passiveness and inertness in it, insomuch
that it is impossible for an idea to do anything, or, strictly speaking,
to be the cause of anything: neither can it be the resemblance or
pattern of any active being, as is evident from sect. 8. Whence it
plainly follows that extension, figure, and motion cannot be the cause
of our sensations. To say, therefore, that these are the effects of
powers resulting from the configuration, number, motion, and size of
corpuscles, must certainly be false. `</font>`{=html}

He considers that \"the cause of ideas is an incorporeal active
substance or Spirit (26)\".

He summarises the concept of an Eternal Spirit that governs real things
and a representational mind that copies the form of the world as
follows:

`<font face="times new roman">`{=html}\"33. The ideas imprinted on the
Senses by the Author of nature are called real things; and those excited
in the imagination being less regular, vivid, and constant, are more
properly termed ideas, or images of things, which they copy and
represent. But then our sensations, be they never so vivid and distinct,
are nevertheless ideas, that is, they exist in the mind, or are
perceived by it, as truly as the ideas of its own framing. The ideas of
Sense are allowed to have more reality in them, that is, to be more
strong, orderly, and coherent than the creatures of the mind; but this
is no argument that they exist without the mind. They are also less
dependent on the spirit, or thinking substance which perceives them, in
that they are excited by the will of another and more powerful spirit;
yet still they are ideas, and certainly no idea, whether faint or
strong, can exist otherwise than in a mind perceiving it.
`</font>`{=html}

Berkeley considers that the concept of distance is a concept in the mind
and also that dreams can be compared directly with sensations:

`<font face="times new roman">`{=html}\"42. Thirdly, it will be objected
that we see things actually without or at distance from us, and which
consequently do not exist in the mind; it being absurd that those things
which are seen at the distance of several miles should be as near to us
as our own thoughts. In answer to this, I desire it may be considered
that in a dream we do oft perceive things as existing at a great
distance off, and yet for all that, those things are acknowledged to
have their existence only in the mind.\"`</font>`{=html}

He considers that ideas can be extended without the mind being extended:

`<font face="times new roman">`{=html}\"49. Fifthly, it may perhaps be
objected that if extension and figure exist only in the mind, it follows
that the mind is extended and figured; since extension is a mode or
attribute which (to speak with the schools) is predicated of the subject
in which it exists. I answer, those qualities are in the mind only as
they are perceived by it- that is, not by way of mode or attribute, but
only by way of idea; and it no more follows the soul or mind is
extended, because extension exists in it alone, than it does that it is
red or blue, because those colours are on all hands acknowledged to
exist in it, and nowhere else. As to what philosophers say of subject
and mode, that seems very groundless and unintelligible. For instance,
in this proposition \"a die is hard, extended, and square,\" they will
have it that the word die denotes a subject or substance, distinct from
the hardness, extension, and figure which are predicated of it, and in
which they exist. This I cannot comprehend: to me a die seems to be
nothing distinct from those things which are termed its modes or
accidents. And, to say a die is hard, extended, and square is not to
attribute those qualities to a subject distinct from and supporting
them, but only an explication of the meaning of the word die.
`</font>`{=html}

Berkeley proposes that time is related to the succession of ideas:

`<font face="times new roman">`{=html}\"98. For my own part, whenever I
attempt to frame a simple idea of time, abstracted from the succession
of ideas in my mind, which flows uniformly and is participated by all
beings, I am lost and embrangled in inextricable difficulties. I have no
notion of it at all, only I hear others say it is infinitely divisible,
and speak of it in such a manner as leads me to entertain odd thoughts
of my existence; since that doctrine lays one under an absolute
necessity of thinking, either that he passes away innumerable ages
without a thought, or else that he is annihilated every moment of his
life, both which seem equally absurd. Time therefore being nothing,
abstracted from the succession of ideas in our minds, it follows that
the duration of any finite spirit must be estimated by the number of
ideas or actions succeeding each other in that same spirit or mind.
Hence, it is a plain consequence that the soul always thinks; and in
truth whoever shall go about to divide in his thoughts, or abstract the
existence of a spirit from its cogitation, will, I believe, find it no
easy task. `</font>`{=html}

`<font face="times new roman">`{=html}\"99. So likewise when we attempt
to abstract extension and motion from all other qualities, and consider
them by themselves, we presently lose sight of them, and run into great
extravagances. All which depend on a twofold abstraction; first, it is
supposed that extension, for example, may be abstracted from all other
sensible qualities; and secondly, that the entity of extension may be
abstracted from its being perceived. But, whoever shall reflect, and
take care to understand what he says, will, if I mistake not,
acknowledge that all sensible qualities are alike sensations and alike
real; that where the extension is, there is the colour, too, i.e., in
his mind, and that their archetypes can exist only in some other mind;
and that the objects of sense are nothing but those sensations combined,
blended, or (if one may so speak) concreted together; none of all which
can be supposed to exist unperceived.\" `</font>`{=html}

He regards \"spirit\" as something separate from ideas and attempts to
answer the charge that as spirit is not an idea it cannot be known:

`<font face="times new roman">`{=html}\"139. But it will be objected
that, if there is no idea signified by the terms soul, spirit, and
substance, they are wholly insignificant, or have no meaning in them. I
answer, those words do mean or signify a real thing, which is neither an
idea nor like an idea, but that which perceives ideas, and wills, and
reasons about them. \....`</font>`{=html}

## Thomas Reid (1710-1796)

!ReidThomas Reid is generally regarded as the
founder of Direct Realism. Reid was a Presbyterian minister for the
living of Newmachar near Aberdeen from 1737. He is explicit about the
\'directness\' of his realism:

`<font face="times new roman">`{=html}\"It is therefore acknowledged by
this philosopher to be a natural instinct or prepossession, a universal
and primary opinion of all men, a primary instinct of nature, that the
objects which we immediately perceive by our senses are not images in
our minds, but external objects, and that their existence is independent
of us and our perception. (Thomas Reid Essays, 14)\"`</font>`{=html}

In common with Descartes and Malebranche, Reid considers that the mind
itself is an unextended thing:

`<font face="times new roman">`{=html}\".. I take it for granted, upon
the testimony of common sense, that my mind is a substance-that is, a
permanent subject of thought; and my reason convinces me that it is an
unextended and invisible substance; and hence I infer that there cannot
be in it anything that resembles extension (Inquiry)\".`</font>`{=html}

Reid is also anxious to equate the unextended mind with the soul:

`<font face="times new roman">`{=html}\"The soul, without being present
to the images of the things perceived, could not possibly perceive them.
A living substance can only there perceive, where it is present, either
to the things themselves, (as the omnipresent God is to the whole
universe,) or to the images of things, as the soul is in its proper
sensorium.\"`</font>`{=html}

Reid\'s Direct Realism is therefore the idea that the physical objects
in the world are in some way presented directly to a soul. This approach
is known as \"Natural Dualism\".

Reid\'s views show his knowledge of Aristotle\'s ideas:

`<font face="times new roman">`{=html}\"When we perceive an object by
our senses, there is, first, some impression made by the object upon the
organ of sense, either immediately, or by means of some medium. By this,
an impression is made upon the brain, in consequence of which we feel
some sensation. \" (Reid 1785)`</font>`{=html}

He differs from Aristotle because he believes that the content of
phenomenal consciousness is things in themselves, not signals derived
from things in the brain. However, he has no idea how such a phenomenon
could occur:

`<font face="times new roman">`{=html}\"How a sensation should instantly
make us conceive and believe the existence of an external thing
altogether unlike it, I do not pretend to know; and when I say that the
one suggests the other, I mean not to explain the manner of their
connection, but to express a fact, which everyone may be conscious of
namely, that, by a law of our nature, such a conception and belief
constantly and immediately follow the sensation.\" (Reid
1764).`</font>`{=html}

Reid\'s idea of mind is almost impossible to illustrate because it lacks
sufficient physical definition. It is like naive realism but without any
communication by light between object and observer. Reid was largely
ignored until the rise of modern Direct Realism.

![](Constudreid.png "Constudreid.png")

Reading between the lines, it seems that Reid is voicing the ancient
intuition that the observer and the content of an observation are
directly connected in some way. As will be seen later, this intuition
cannot distinguish between a direct connection with the world itself and
a direct connection with signals from the world beyond the body that are
formed into a virtual reality in the brain.

## References

-   Descartes, R. (1628). Rules For The Direction of The Mind.
-   Descartes, R. (1637). DISCOURSE ON THE METHOD OF RIGHTLY CONDUCTING
    THE REASON, AND SEEKING TRUTH IN THE SCIENCES.
-   Descartes, R. (1641). Meditations on First Philosophy.
-   Descartes, R. (1664) \"Treatise on Man\". Translated by John
    Cottingham, et al. The Philosophical Writings of Descartes, Vol. 1
    (Cambridge: Cambridge University Press, 1985) 99-108.
-   Kant, I. (1781) Critique of Pure Reason. Trans. Norman Kemp Smith
    with preface by Howard Caygill. Pub: Palgrave Macmillan.
-   Locke, J. (1689). An Essay Concerning Human Understanding
-   Reid, T. (1785). Essays on the Intellectual Powers of Man. Edited by
    Brookes, Derek. Edinburgh: Edinburgh University Press, 2002.
-   Reid, T. (1764). An Inquiry into the Human Mind on the Principles of
    Common Sense. Edited by Brookes, Derek. Edinburgh: Edinburgh
    University Press, 1997.
-   Russell, B. (1945). A History of Western Philosophy. New York: Simon
    and Schuster.

**Further Reading**

See: \"Thomas Reid\" at
Wikisource

-   Cartesian Conscientia by Robert Hennig