I apologize for diverting this list into a discussion of mind-body. I came onto the list to explore Tegmark's thesis about our persons' being endlessly duplicated. It seems to me that this thesis depends not just on cosmology but also on what we know about persons. It struck me that the discussion here assumed without question (i) reductionism and (ii) determinism.
I don't think these assumptions hold even in physics. You can all correct me if I am wrong, but my understanding is that the Pauli Exclusion Principle is not explainable by the properties of atomic parts. It is an emergent property of an entire atom. Similarly, there is good reason to think that determinism does not hold at the quantum level.
Whatever is the case in physics, after long debate, (i) and (ii) above have been rejected at the human level by most current social scientists. So the relevance of my line of questioning was what difference it makes to Tegmark's thesis if assumptions (i) and (ii) are relaxed.
One difference it might make is that the whole universe is not computable because our own behavior is not computable. Another difference is that without determinism, even in a universe with the same initial conditions, we might not show up again.
And if reductionism fails, then what are called propositional attitudes (wants, beliefs, etc) are not identifiable with physical properties. So What? That is the question Pete asks.
I don't see how "reductionism fails" entails "thoughts are uncountably infinite".Is it because you are identifying thoughts with sentences and sentences are infinite? But not every sentence is a thought. Most sentences are not thinkable or believable. I'm not sure sentences are uncountably infinite, either.
Well, thoughts encompass much more than sentences -- which is why human thought does not seem computable. But it does seem that sentences are thoughts. I don't know what you mean by most sentences are not thinkable or believable. It seems for someone to produce a sentence, he or she must think it.
We can get around this though by talking just about thinkable sentences. Do you not agree that even thinkable sentences are infinite? Would you have any idea how to count them? Even thinkable sentences seem both infinite and uncountably infinite to me. Hence thoughts are both infinite and uncountably infinite.
Pete, you go onto ask:
To start off with, why should we commit ourselves to talking about beliefs as individuable entities in the first place? I prefer Dennett's intentional stance theory of beliefs - beliefs are abstract things we posit that explain or predict behavior.
Well I can go along with propositional attitudes being abstract properties we posit to explain or predict behavior. For that purpose, though, propositional attitudes need to be attributed individually.
You seem to imply in what follows that propositional attitudes are somehow not real but only in the mind of the observer.
To relate this to Tegmark/Schmidhuber, look at it like this: The physical (or Platonic/mathematical, it really doesn't matter) stuff is there; it's the underlying reality. If sub-sections of the stuff (i.e., us) see patterns in it and talk about these patterns as "individuals" and "beliefs", that's our business. It doesn't have any bearing on the nature of the underlying stuff. It's not a terribly important result that we can imagine infinite numbers of patterns (such as beliefs) -- after all, you can imagine an uncountably infinite number of strings composed of just 0 and 1.
Sure, some patterns are just in our minds without any consequence. What determines whether the "stuff" is actually there is whether it is consequential. To the extent that propositional attitudes are both predictive and explanatory, they are consequential.
I like Dennett's intentional stance, but in some cases -- as in dealing with other people, the stance works because intentionality is what actually causes the behavior.
Next, beginning with a comment of mine to Norman, Eugen accuses me of not knowing mainstream science.
:Okay, well here you have just asserted that human beings can be defined as the sum of discrete quantum states and the like and that thoughts are therefore not infinite.
You make it sound like a fringe statement, the reverse is in fact the case. Bekenstein's limit (and subsequent works based on that) is mainstream science.
I admit that to the extent that humans are physical, they can be represented by quantum states. But they are not entirely physical. As Pete suggests above, they also have states of being that, although not mystical, are abstract or at least non-physical.
And, yes, I'm sorry but it is not too early to judge eliminative materialism and the identity theory as failures. That is why most philosophers have now abandoned them. Pete also suggests as much:
Here I'm interpreting your "reductionism fails" as "eliminative materialism and identity theory are false", which I tend to agree with; I notice you didn't mention functionalism however.)
No, I did not mention functionalism in part because I was summarizing. Functionalism has its problems too, but I agree it is much stronger than the other two. But it is stronger precisely because it has already moved beyond reductionism. Many functionalists regard it as a form of nonreductive materialism. It was functionalism that introduced the software / hardware analogy I mentioned.
You ask me to explain what I mean by holistic and closure in relation to thought.
In the philosophy of science, closure refers to whether a system has a delimited number of causal mechanisms operating. Experiments, for example, are typically artificially closed systems in which only one mechanism operates without interference. The real world outside the lab is typically open causally -- although it some case like planetary orbits perhaps -- the interference does not matter much.
The point of this distinction is that Humean causal laws (linking events) are possible only in closed systems. In open systems, the putative laws will always be interfered with and hence fail to be lawlike. This does not mean there is no causality, but it does indicate a problem with the conventional Humean conception of causality.
The point I was making about ideas is that to the extent that they are effectively infinite, human decision-making is intrinsically open to new thought and hence not conformable to Humean laws, or, in other words, nondeterministic.
In the context of thoughts, by holistic I meant context dependent. The effect of an idea is conditioned by what other ideas surround it. The import of ideas and their effects cannot be computed one by one. Jerry Fodor makes a similar point in his THE MIND DOES NOT WORK THAT WAY.
Kevin, I don't know whether your post was a direct response to me. I share your notion of increasing cosmic complexity. That very notion seems to imply emergence rather than reductionism. So, other than perhaps politically, I don't see a disagreement.
-- doug porpora dept of culture and communication drexel university phila pa 19104 USA