# Philosophical Works of the Late James Frederick Ferrier/Institutes of Metaphysic (1875)/Section 1/Proposition 5

The Institutes of Metaphysic, Philosophical Works of the Late James Frederick Ferrier (1875 ed., Vol. 1). (E. L. Lushington, & A. Grant, Eds.) Edinburgh: William Blackwood and Sons. pp. 144-155.
PROPOSITION V.
MATTER AND ITS QUALITIES PER SE.
DEMONSTRATION.
The qualities of matter by themselves are, equally with matter itself, an objective presentment without a subject. But it has been proved by Proposition II. that no objective can be known without a subjective or self being known along with it. Therefore, all the qualities of matter, by themselves, are absolutely unknowable.
OBSERVATIONS AND EXPLANATIONS.
Why Proposition V. is introduced.1. In dealing with the question respecting our knowledge of material existence, psychology vacillates between two opinions. At times it sides with natural thinking, and affirms, in the terms set forth ​in Counter-proposition IV., that matter per se is known; and at other times it advocates a doctrine for which natural thinking is certainly in no way responsible—the opinion, namely, that we are cognisant only of the material qualities per se. The first of these opinions is set at rest by Proposition IV., which proves that a contradiction is involved in the supposition that material things, by and in themselves, or without a mind being known along with them, can be known by any intelligence. The proposition now before us is introduced chiefly for the purpose of meeting and correcting the second of these opinions, to which a distinct expression is given in the following counter-proposition. It will be at once obvious that this counter-proposition involves a contradiction just as much as Counter-proposition IV. does; because it asserts that certain qualities of matter can be known without the "me" being known along with them. But it has been thought necessary to bring forward this doctrine, and to controvert it expressly, because it is one which is generally considered as placed beyond the reach of controversy by means of a psychological distinction of some celebrity, the value of which shall now be critically tested.
Fifth counter-proposition.2. Fifth Counter-proposition.—"Although matter per se is not known, certain of its qualities are knowable, and are known per se, or by themselves."
​Distinction between the primary and the secondary qualities of matter.3. The qualities here referred to are those which our psychologists call the primary qualities of matter. It is here, then, that the distinction between the primary and secondary qualities comes under review. This distinction has played a conspicuous, though neither a very edifying nor a very successful part in philosophy. It is of some importance, however, in a historical point of view, as forming a chapter in the controversy between idealism and materialism; and therefore a short account of it shall now be given—if for no other purpose than that of showing how completely it has failed to answer its purpose, and how much it tends to keep up mistaken and contradictory notions in regard to the laws of knowledge.
Character of the secondary qualities.4. It is not necessary to present a complete enumeration of the primary and secondary qualities, or to go into any detailed explanation of their nature. A general view of the respective characters of the two classes will be sufficient to enable the reader to understand the distinction, and the use to which it has been turned by psychology. Among the secondary qualities are classed heat and cold, colour and sound, taste and odour. It will be observed that these words are of ambiguous or twofold import. They signify both certain sensations in us, and certain inferred qualities in things by which these sensations are induced. Thus the words ​"heat" and "colour" express the subjective affections which we call by these names; and they also express certain occult material causes which are supposed to excite them. When we speak of heat in our hand, we mean something very different from what we mean when we talk of heat in the fire. In the one case we mean a sensation; in the other case we mean some inferred property in the fire which occasions that sensation. And so in regard to the other secondary qualities. The words which express them are generally ambiguous, and it is only from the context, or from the relation in which they are spoken, that we are able to determine in which of the two senses (objective or subjective) the terms are employed. In this respect the secondary qualities are said to differ from the primary. But the important circumstance, in the estimation of psychology, and to which our attention is directed in considering this distinction, is, that we have no distinct and assured knowledge of the secondary qualities as they are in themselves, inasmuch as they must be, in their own nature, very different from the sensations to which they give rise. The sensations are all that we are cognisant of: and thus our knowledge of material things, and even the evidence of their existence, would be extremely imperfect, doubtful, and confused, had we no other sources of information respecting them than the subjective affections which their occult qualities are supposed to induce, and no ​other notion of them than the notion of their secondary qualities.
Character of the primary qualities.5. The primary qualities are said to be of a different character, and to supply the information and the evidence which are wanted. These are principally extension, figure, and solidity. We are cognisant of these qualities, not as mere sensations in ourselves, like heat and cold, colour and sound, but as they exist and show themselves in external things. Heat and cold, colour and sound—in a word, all our sentient modifications—may be so increased in degree as to become unbearable. But our perceptions of the extension and figure and incompressibility of material objects cannot be thus augmented in intensity. By this circumstance our perceptions are distinguished from our sensations: the latter are susceptible of different degrees of vivacity; some amount of bodily pleasure or pain enters into their composition. Not so in the case of our perceptions. Their degree is always the same; they involve no organic pleasure, or the reverse. It is through our perceptions, and not through our sensations, that we are made acquainted with the primary qualities of matter—that is, with the extension, the figure, and the solidity of external objects. It is further alleged that the terms which indicate the primary qualities are not ambiguous, but have only one signification. But the important circumstance to which psychology ​refers us in its exposition of the primary qualities, is this, that we have a distinct and direct knowledge of them as they exist, not in our minds, but in the things which are made known to us through their means. We have a clear apprehension of the objective presence of extension, figure, and solidity, as the properties of external things. In this respect the primary differ from the secondary qualities, of whose objective existence we have no distinct knowledge or conception.
Such is the psychological distinction between the primary and the secondary qualities of matter, and between sensation and perception. Sensation is the faculty which doubtfully and obscurely indicates the objective existence of the secondary qualities; while perception is the faculty which announces dearly and unmistakably the objective existence of the primary. Sensation, it is said, reveals the sentient subject; perception the sensible and objective world.
Defects of this distinction.6. In itself, and under certain limitations, this distinction is harmless. Although the analysis is of no importance, and answers no purpose, there is nothing positively erroneous in the affirmation that the primary qualities of matter are phenomena of a different order from the secondary; that the latter are obscure and sensational; that the former are clear and perceptible. Psychology might, indeed, ​find it difficult to show that the words which express the primary qualities are one whit less ambiguous than those which denote the secondary. Are not the words "extension," "figure," and "solidity," employed both to express these qualities as they are in themselves, and also to express our perceptions of them? Is not this precisely the same ambiguity which the terms significant of the secondary qualities present? Is psychology able to explain, or is any human being competent to know what these qualities are, apart from his perceptions of them? It is always our perceptions of the primary qualities, and not these qualities themselves, which come before the mind, just as it is always our sensations resulting from the secondary qualities, and not the secondary qualities themselves, that we are cognisant of. The terms, therefore, which express the primary qualities, are just as ambiguous as those which indicate the secondary; and the attempt to remove this ambiguity, by means of the distinction in question, instead of removing, serves only to disguise it The attempt to establish a clear doctrine of perceptive knowledge, by distinguishing the two classes of qualities, establishes only an obscure and misleading one.
7. But the error lies not so much in this distinction itself as in its application. In the hands ​It runs into a contradiction.of psychology it runs into a palpable contradiction—into the contradiction to which expression is given in this fifth counter-proposition, which declares that certain qualities of matter can be known, without the me or subject being known along with them. How this contradiction comes about will be obvious from the following considerations.
Psychological conception of idealism.8. This distinction has been employed by psychology in refutation of what it conceives to be idealism. Idealism, according to psychology, is founded on a refusal to recognise the primary qualities of matter as clearly distinguishable from the secondary. It is supposed to confound the two classes under a common category, or rather to reduce the primary qualities to the same character and condition as the secondary—to resolve extension, figure, and solidity, no less than heat, and colour, and sound, into mere modifications of the sentient subject. It is supposed to maintain that the primary qualities are just as obscure and occult as the secondary; that in dealing with the material universe we are cognisant, not of the qualities of external objects, but only of certain changes in our own sentient condition, and thus idealism is supposed to have succeeded either in abolishing or in rendering doubtful the absolute existence of material things;—because, if the primary qualities stand ​on precisely the same footing with the secondary; if we know nothing about either class as they are in themselves; and if the attempt to reduce our whole knowledge of the material world to a mere series of sensations be successful, these sensations may possibly be excited by other causes, and accounted for on other pounds than the postulation of an independent universe; and therefore the existence of the latter becomes, at any rate, problematical. With the annihilation of the sentient subject, the material universe would disappear—would be reduced to a nonentity, because it consists of a mere series of sensations.
Such is the psychological conception of idealism. This system is supposed to aim at the extinction of material things, and to withdraw them from our cognition, by confounding or repudiating the distinction between the primary and secondary qualities. The psychologist conceives that idealism is founded on a false generalisation to this effect:—some of the qualities of matter, such as heat, sound, and colour, turn out, on examination, to be mere sensations in us, therefore the whole of the material qualities are susceptible of this resolution.
Psychological refutation of idealism.9. Having thus detected what he conceives to be the fallacy involved in the idealist's argument—namely, the false generalisation on which it proceeds, in other words, the shuffling together of the ​primary and secondary qualities, the psychologist then addresses himself to its refutation, and to the restoration of the material world to the independency of which it appeared to have been so unlawfully deprived. He brings into play the distinction which we have been considering. He admits that some of the qualities of matter are reducible to mere sensations; but he denies that the whole of them admit of this resolution. No, says he, there is extension, there is figure, there is solidity. These qualities are refractory. They will not submit to be classed along with those more tractable companions of theirs, heat, cold, colour, &c, as the mere sensations of man. They refuse to be resolved into mere modifications of the human mind; and the attempt so to resolve them is to confound together phenomena which are essentially different They speak out plainly for themselves; they claim a manifest existence of their own. There is nothing occult about them. Unlike the secondary qualities, they declare their presence unequivocally. They stand forth and defy the idealist, with all his machinations, to explode them. Our sensations may perhaps not afford us any clear information in regard to the nature of material things, or even any sufficient evidence of their existence; but our perceptions of extension, figure, and solidity, place this truth in a clear light and on an indisputable footing; and, on the manifest existence of these ​qualities, we rest the establishment of the independent existence of matter.
This refutation, if logically conclusive, is founded on a contradiction and therefore cannot be accepted.10. There appears at first sight to be some force in that argument, but before it can be accepted as valid, one or two small circumstances must be taken into consideration. It is not enough to show that sensation is different from perception, and that the primary are different from the secondary qualities; the psychologist must moreover show, or, at least, must assume, that the primary qualities are known per se, or without the "me" being known along with them. Unless he assumes this his argument is good for nothing. His object is to prove that material things have an existence altogether independent of intelligence. Perhaps they have; but how can that conclusion be logically reached by merely affirming that extension, figure, and solidity are not of a sensational character, and that the primary qualities are different from the secondary? This doctrine must be coupled with the assertion, that the primary qualities are known in their independency, otherwise the conclusion that they are independent can have nothing to rest upon. The psychological argument, therefore, when stripped of its wrappings and presented in plain language, amounts to this:—certain qualities of matter, namely, the primary, are known to exist per se; therefore these qualities, and the matter in which they inhere, do exist per se. But ​the premise of that argument (we have nothing to do with the conclusion at present) is false and contradictory. It contradicts Proposition V., which is a necessary and demonstrated truth of reason. It is not possible for any of the qualities of matter to be known per se, or without a "me" or subject being apprehended along with them. Therefore the psychological reasoning in support of the independent existence of matter rests on a foundation which falsifies the necessary laws of knowing; and thus it not only fails to answer the purpose for which it was designed, but it poisons the stream of philosophical truth in its very fountain-head.
The distinction of the primary and secondary qualities should be abandoned as useless, or worse.11. So much, then, for the distinction between the primary and secondary qualities of matter, and the uses to which it has been applied. This distinction is one on which psychology usually lays much stress as leading to important consequences. It is, however, a distinction which answers no purpose. It holds out promises which it is unable to fulfil. It affords no refutation even of the spurious idealism which it assails. When viewed in its true colours, it is seen to falsify the laws of knowledge, and to mislead the footsteps of philosophy. It is, at best, a mere bubble on the sea of speculation; and it should now be allowed quietly to break and die. It has played its part as well as it could, and that was not very well.