I again apologize for the delay. I’m very interested in this topic and I do want to be very involved in the discussion. I’m, unfortunately, rebuilding my deck which is taking most of my ‘free’ time.
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Originally Posted by Doctordick
It is very important that no possibility be eliminated: i.e., the model must be without any presumptions so there is a need to be careful.
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I take a presumption as an assumption that is taken for granted. I therefore agree they should be avoided. I really don’t have a problem, on the other hand, with assumptions so long as they are clearly recognized for what they are so that the completed model is understood to require the validity of those assumptions.
Quote:
Originally Posted by Doctordick
The first issue to be handled is the fact that we must allow for a change in the information being explained; no matter what is being explained, it is possible that we might obtain additional information and our model must accommodate that fact.
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This is a big step for me. I didn’t realize you would be modeling a changing explanation or accounting for changing information (other than the change that accompanies the transformation of unexplained info to explained info). I would have expected concepts of change and ‘time’ to be part of the information needing an explanation and not necessarily an a priori mechanism of the model. But, I’m looking with an open mind and certainly willing to give all benefit of any doubt...
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Originally Posted by Doctordick
I define time through the following procedure: I define “the past” to be the information to be explained, “the future” to be information not available and “the present” to be a change in the information available to be explained. (The concept “information” has not yet been defined; remember, we want to make no presumptions.)
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You keep stressing “no presumptions” and I’m less and less sure what you mean by that.
I could define the future as information informing the explanation, the past as information not yet available, and the present as a change in the information being explained (i.e. information loss). That would make perfect sense to me if the arrow of time were reversed. The future would cause the present. For example, a shattered and spilled glass of water on the floor amounts to information which needs explained. There are a number of possibilities predicted by the explanation. There is then a change in the information where the mess on the floor changes into a single glass of water sitting on the table. The system being described has now lost information (a well-ordered system amounts to less information than the same system in a disordered state). There are now less possibilities predicted by the explanation.
This explanation could be imagined as going further and further back into the past finally reaching a point where the system has zero entropy and any information is completely explainable and predictable. The probability of successfully predicting any given unknown element would be 100%.
So it seems to me that your definition of past, present, and future rely in a subtle way on our intuitive notions of causality. Saying that information in the past is what gets changed (and specifically: added to) is comparable to the idea of information in the past causing the change in the present. But, if we’re not relying on our senses and intuition to tell us this is the way it should work then we would just as easily conclude using pur force of logic that information from the future gets changed—that it causes the change. So, this does seem like an assumption is being made about the arrow of time pointing toward the future.
Quote:
Originally Posted by Doctordick
This definition seems to me to be the only way of encompassing the possibility of an explanation changing... the idea of time being a sequence of “presents”; the idea that the past cannot be changed and, finally, the fact that the future is “unknown”.
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I'm having a hard time seeing "past" and "future" as necessary for encompassing the possibility of the explanation changing. I could, for example, write a computer program to generate the first n primes and each instance of the program (or each iteration) it could increase n by 1 by altering itself. In this case the explanation of the data were we to examine it would be the program. The function of the program is also the explanation of the data. The data changes (as does the explanation) without the need for the program being modeled after definitions of past and future.
I don't see how such concepts are necessary to maintain the integrity of the concept of change. I'm also not sure about "change" being necessary to maintain the integrity of an explanation.
~modest
PS—I'm not dismissing your approach, just thinking critically about it.
