Hi

Below is the time-lag argument for indirect perception, made popular by Bertrand Russell - can anyone identify any flaws in it?



1) Perception is dependent on information about the external world reaching the sensory areas of the brain, via the sense organs, and then being processed there, all of which does not happen instantaneously, but takes at least around a tenth of a second.

2) Therefore, what one experiences perceptually must lag behind the external world by at least around a tenth of a second.

3) If X and Y are actually literally the same thing, then there cannot be any kind of distinction whatsoever, however small, between X and Y.

4) Therefore, what one experiences perceptually cannot literally be the area of the external world being perceived.

5) Therefore, what one experiences perceptually must be a delayed representation of the area of the external world being perceived, generated by the brain from sensory information.

6) Therefore, perception is merely a mental simulation of the external world.



Derrick

Hi

Below is the time-lag argument for indirect perception, made popular by Bertrand Russell - can anyone identify any flaws in it?



1) Perception is dependent on information about the external world reaching the sensory areas of the brain, via the sense organs, and then being processed there, all of which does not happen instantaneously, but takes at least around a tenth of a second.

2) Therefore, what one experiences perceptually must lag behind the external world by at least around a tenth of a second.

3) If X and Y are actually literally the same thing, then there cannot be any kind of distinction whatsoever, however small, between X and Y.

4) Therefore, what one experiences perceptually cannot literally be the area of the external world being perceived.

5) Therefore, what one experiences perceptually must be a delayed representation of the area of the external world being perceived, generated by the brain from sensory information.

6) Therefore, perception is merely a mental simulation of the external world.



Derrick

I'm not a Russell expert... I understand his thoughts changed over time. But I know that at least in one part of his life, he acknowledged the situation and saw significance in Plato's response to it: thinking in terms of the proposition.

An associated line of pondering leads to the question: can we really ever arrive at a state where we aren't building off of axioms? Is the infrastructure of thought just assumptions? There's a longing for some solid ground. What makes the axioms seem less than solid is the realization that their solidity appears to come from us. There's a sentiment that solidity needs to come from outside.

Maybe this longing for solidity from outside is related to a baby's longing for solidity when it can't control its muscles yet. Maybe a large portion of philosophy is the legacy of this experience.

Maybe what we're experiencing here is just a side-effect of the evolution of human thought. We once recognized that we received fire from a divine source. Then we realized: no, we made fire. We subsumed creativity into our self perception. What our ancestors thought came from outside, we say came from inside us. And a lot of philosophy is the legacy of this experience.

Or maybe the whole situation arises from the post-event perspective: we look back and see that we are always suspending disbelief. We then try to figure out how we do that. Are we asking a legitimate question here, though? Is there always some sort of uncertainty about the laws of physics lurking in my being? I say I'm free to suggest that I don't ever suspend disbelief. There's actually no disbelief to suspend. Disbelief only exists in my mind during retrospection... not in the present... not in the pre-event perspective.

And the time-lag argument? What about that?

"The view that knowledge is sense perception is really the same as the formula of Protagoras, that man is the measure of all things. In sense perception things appear as they appear, so that we cannot go wrong. In the ensuing discussion it becomes clear that the proposed definiton of knowledge is not adequate. To begin with, it will not do to say that something is as it appears, since nothing really is; things are always in a state of becoming, as Heraclitus had said. Sense perception is, in fact, an interaction between perceiver and perceived. Moreover, Protagoras himself would have admitted that in matters where a decision must be made, one man's view is not as good as another's, the expert is a better judge than the layman. Besides, a man untainted by philosophic thought will hardly give assent to the formula, so on his own showing Protagoras must admit that for such a person the theory is not true. The upshot of the discussion is this: if we try to describe knowledge in terms of Heraclitean theory of flux we find that nothing can be said. Before anything can be pinned down by a word it has melted away into something else. We must therefore try some other way of answering the question what is knowldge.

Let us then consider the fact that while the senses each have their proper objects, anything that involves connection between perceptions by different senses requires the funciton of some overall sense. This is the soul or mind, the two are not distinct in Plato. The soul apprehends such general predicates as identity, difference, existence, number as well as the general predicates of ethics and art. Hence it is not possible to define knowledge simply as sense perception. Let us therefore try to see whether we can find definition on the side of the soul. The function of the soul is to conduct dialogues with itself. On reaching a settlement of a question we say that it has made a judgement. We must now examine whether we may define knowledge as true judgement. On investigation we find that it is impossible on this theory to give a satisfactory account of false judgement, or error. That errors are made is obviously granted by all. The distinciton between truth and error is not worked out at this stage. Plato merely clears the ground, his own account of the problem may well not have fully developed at that time.

But false judgement is impossible if judgement is an activity of the soul alone. We might suppose that the mind was like a tablet with memory marks impressed on it. Error might then consist in connecting a present sensation to the wrong imprint. But this fails for mistakes in arithmetic when there is nothing to have sensations of. If we suppose the mind to be some sort of birdcage, the birds in which are pieces of knowledge, then we might occasionally net the wrong bird, and that would be error. But then, to commit an errori s not the same as to utter an irrelevant truth. We must therefore suppose that some of the birds are pieces of error. But if we catch one of these we know that it is an error as soon as it is caught, so that we could never be in error. Besides, we may note the point which the argument overlooks, that if one introduces pieces of error, then the entire story becomes circular as an account of error.

..... Referring back to the 'Theaetetus", we may recall that knowledge, whatever else it may also require, at least requires interaction and therefore Motion. But it also requires Rest, since otherwise there would be nothing to be talked about. Things must in some sense stay put if they are to be objects of enquiry. This gives us a hint for attacking the problem. For Motion and Rest undoubtedly both exist, but as they are opposites, they cannot be combined. Three possibilites for combination seem to suggest themselves. Either all things remain completely separate, in which case Motion and Rest cannot have a part in Being. Or all things can merge, in which case Motion and Rest could come together, which they clearly cannot. It therefore remains that some things can, and others cannot, combine. The solution of our difficulites lies in recognising that Being and Not-being are meaningless expressions on their own. It is only in a judgement that they make sense. The 'forms' or kinds, like Motion, Rest, Being, are the general predicates already mentioned in the 'Theaetetus.' They are clearly quite different from the forms of Socrates. This Platonic theory of forms is the starting point of what later developed into the theory of categories.

The function of dialectic is to study which of these forms or "highest kinds" combine, and which do not. Motion and Rest, as we have seen already, do not combine with each other, but each of them combines with Being, each is. Again Motion is the same as itself but other than Rest. Sameness, or Identity, and Otherness, or Difference, like Being, are all-pervasive. For each is identical with itself and different from all the others.

We can see now what is meant by Not-being. Motion, we might say, both is and is not. For it is Motion, but it is not Rest. In this sense, then Not-being is on the same level as Being. But it is plain that the Not-being here evolved must not be taken in complete abstraction. It is a Not-being such and such, or better, a Being other than such and such.

Plato has thus brought out the source of the difficulty. In modern jargon, we must distinguish the existential us of "is" from the use of it as a copula in a porposiiton. It is the second of these that is logically important.

On this basis we can now give a simple account of error. To judge truly is to judge something to be as it is. If we judge something to be as it is not, we judge falsely, and so we commit error. It may surprise the reader that the outcome is no more formidable or mysterious than that. But hen as much holds of any problem once we know the solution." --Bertrand Russell.. "Wisdom of the West"

What has this to do with the time-lag argument?

LOL! What is time?

I really dont understand the point in Russels argument. Yes, the information we receive from the external world has a lag time but so what? Unless there's some implication I missed I really dont get the point of what he was getting at.

I really dont understand the point in Russels argument. Yes, the information we receive from the external world has a lag time but so what? Unless there's some implication I missed I really dont get the point of what he was getting at.

Exactly: what you observe doesn't exist.

You cannot observe what does not exist. You can believe you observe what does not exist, though. Russell does not say we are observing what does not exist (that's nonsense). What he is arguing that is that what we think we observe may not exist. That's different.

How do we ever know that what we observe actually exists? In the case of the star, yes, it's possible the star stops existing (during the 8 minute lag), and we could easily extrapolate this to anything, couldn't we?

When do we know we're observing as opposed to just believing we're observing (in the case of the thing not existing)?

How do we ever know that what we observe actually exists? In the case of the star, yes, it's possible the star stops existing (during the 8 minute lag), and we could easily extrapolate this to anything, couldn't we?

When do we know we're observing as opposed to just believing we're observing (in the case of the thing not existing)?

Interesting... if we follow this to its logical conclusion, then any perception that has any time-lag is therefore a simulation; believe this, and nothing can be held to be a true-representation. And since no light, sound or tactile impulse happens immediately, it would apply to everything.

While this is likely ultimately true, my sense is that its implications thrust the believer further into obscurity. We can all accept that what we perceive isn't absolutely-accurate given perceptional flaws and mental filters, but this is - to me - a far cry from relegating such perceptions to the category of "simulation".

Hmmm... yea I'll need to think on this one. Good post - thanks

But see:

http://www.tcnj.edu/~lemorvan/APR_Proof.pdf

especially page 223 for an analysis and rebuttal of the time-lag argument.

Russell's conclusion is that we are not seeing the star, since it took 8 minutes for the light to reach our eyes. After all, the star might have stopped existing in those 8 minutes. So that when we believe we are seeing the star, we are mistaken. We are really seeing the light from the star. The star may no longer exist. And, since it takes a finite time for light to reach us from any object however near we are to it, we are not seeing any object at all.

It is a good thing to ask questions when you do not understand. I congratulate you for doing so.