From: markrose@spss.com (Mark Rosenfelder)
Newsgroups: comp.ai.philosophy
Subject: Re: what it means to be grounded
Date: 7 Jan 93 22:00:39 GMT
Organization: SPSS Inc.

In article <1ii5d1INNdl5@shelley.u.washington.edu> forbis@stein.u.washington.edu 
(Gary Forbis) writes:
>In article <C0Hx49.GBw@spss.com> markrose@spss.com (Mark Rosenfelder) writes:
>>Human symbol systems are of course not *inherently* grounded-- "runny nose"
>>might mean "tasty breadfruit" in Maya-- but human beings *are* grounded:
>>when we make noises about noses or fire we aren't playing with arbitrary 
>>symbols, but really referring to noses or fire. 
>
>I may be mistaken but the first part of this sentence means "human symbols
>are arbitrary."  When I make noises about noses or fires I associate some
>symbols with noses and fires but my noises are not noses and are not fires.
>The symbols themselves are no more grounded when I use them than when a 
>computer uses them.  

Agreed so far.

>Suppose I accept your assertion that "human beings *are* grounded."  What
>makes computers any less grounded?  When I use the word "pi" and mean the
>ratio of the circumference of a circle to its diameter I don't go through
>some infinite regress of definitions.  

That's right: for you, the regress *stops* in a mass of real-world experience.
You've worked with diagrams of circles, round things, rulers, etc., so
all these things have meaning for you.  (This is stated from Lakoff's
perspective, in which geometry and logic are abstracted from our experience of
everyday things.  If you want a Platonist explanation instead, ask 
Mikhail Zeleny. :)

For the computer the regress stops... period.  Symbols are defined in terms
of other symbols, and then there ain't no more.

>Haven't you ever played the game where
>you ask a person to define a word he or she uses then recursively ask her
>or him to define a word used in the prior definition?

Do you seriously maintain that all words are defined in terms of other
words?  Some are; but others have to point to the real world instead.

>What does "in a pig's eye" mean and why?

Obviously the meaning of idioms can't be derived from the meanings of their 
component words.  So what?

>I will propose the following definition for grounding:
>
>An entity may be said to be grounded with respect to an environment when,
>using its model of the environment, it can make a plan to achieve a goal
>in the environment and then, adjusting the plan as necessary, have an
>effect in the environment and achieve the goal.  The symbols in the model
>may be said to be grounded to their corresponding entities in the environment
>when the entity having the model refers to them when acting upon the
>corresponding entities in the entity's environment.

Now I will surprise you, perhaps, by agreeing with your definition.  Your
definition presupposes a causal connection from the entity to the
environment.  Moreover, this is probably impossible without the ability
to get information about the environment in an ongoing fashion.  There you
go, sensorimotor experience, what I've been going on about for weeks--
the chain of symbols ends outside the entity; a grounded AI has at least
some robotic capacity.

Discussing grounding with Wayne Throop I've come to believe that there are
degrees of grounding; felicitious conversation with a human being, for 
instance, would require not just some but vast loads of world experience.
Newsgroups: comp.ai.philosophy