Homomorphism Theory and the Mental Attitudes

OK, so I have been distracted the last few days with thoughts about Berkely and the relationship of God to quantum mechanics, but today I have to get back to work on my consciousness stuff…April will be here before you know it, and I have still got to turn this into a powerpoint presentaion!

 So, before my ADD kicked in I was addressing Josh and Rosenthal’s response to my question about the difference between conscious pains and conscious thoughts that resukts in one being qualitative while the other isn’t. Their response is that the difference between the two cases is the result of the difference between the kind of property that one attributes to onself. I argued that they still haven’t told me why one isn’t like anything at all for the creature and that it is inconsistent with Rosenthal’s view about the emotions.

However, even if one is not moved by the above considerations, a closer look at Rosenthal’s account of thought and its relation to speech reveals something which closely resembles his homomorphism theory of the sensory qualities. He may be right that we cannot give a hommorphism theory for the content of beliefs, but we may be able to give one for the mental attitudes themselves.

On Rosenthal’s view there is a tight connection between thought and language. So for him thoughts consist in taking some mental attitude towards some propositional content. These thoughts are expressed in speech acts that (most often) have the same propositional content and an illocutionary force that matches the mental attitude of the thought. So, for example, if I think ‘it’s snowing’ (that is, if I believe that it is snowing) I can express that by saying ‘it’s snowing’ and my speech act has assertive illocutionary force that matches the mental attitude of the thought. This is in general true for him. As he says,

When a speech act expresses an intentional state, not only are the contents of both the state and the speech act the same; the speech act and the thought also have the same force. Both, that is, will involve suspecting, denying, wondering, affirming, doubting, and the like. Whenever a speech act expresses an intentional state, the illocutionary force of the speech act corresponds to the mental attitude of that intentional state. (p. 286)

So there are families of mental attitude among which similarities and differences will hold. So believing will be more like suspecting than it will be like wondering.

What are we to say about the actual homomorphism to perceptible properties? Is there any set of properties that the mental attitudes are homomorphic to? That is, is there a set of properties that have similarities and differences which resemble and differ in a way that preserves the similarities and differences between the mental attitudes? This is important since we need a way to specify the attitudes apart from their qualitative component. As I have suggested beofe we can hypothesize that the homomorphic properties are the illocutionary forces of speech acts.

So the differences between beliefs that p and desires that p are homomorphic to the differences between the illocutionary force of the utterance of some linguistic item in the process of expressing the belief or desire. Rosenthal’s overall view even suggests this. For instance he says,

It is arguable that speech acts inherit their intentionality from mental states by being a part of an overall causal network that involves those mental states…If so, then not only is the intentionality of speech acts due to their causal connections with thoughts; the intentionality of mental states themselves consists, in part, in the causal relations those states bear to speech acts. (p97)

Thus there are no relevant difference between these kinds of states. We are left wanting an explanation for why it is that one kind of thought results in there being something that it is like for me to have the conscious experience while in the case of the other kind of thought this is denied. Now perhaps there is an another worked out theory of the qualitative properties that could be able to supply a satisfying answer to this question; but I have not seen it. I am doubtful that one can be given.

God Vs. The Delayed Choice Quantum Eraser

This is the name of an experiment first proposed in 1982, and is the one that I have had in mind when talking about God and quantum mechanics. I realized that most of the comments I have received seem to be taking me to be talking only about the standard double-slit experiment; this is of course my own fault since I haven’t done a very good job of indicating what I had in mind. So, let me describe these results and then reformulate the argument.

We have to build up to this, so let’s start with the quantum eraser experiment. Here is how Brian Greene describes the experiment in his recent book The Fabric of the Universe.

A simple version of the quantum eraser experiment makes use of the double-slit set up, modified in the following way. A tagging device is placed in front of each slit; it marks any passing photon so that when the photon is examined later, you can tell through which slit it passed…when this double-slit-tagging experiment is run, the photons do not build up an interference pattern.

As he goes on to point out, this is what we would expect. Since we measure the photon’s path, we get the photons acting like particles. But then it gets weirder. As Green continues, the quantum eraser asks,

What if just before the photon hits the detection screen, you eliminate the possibility of determining through which slit it passed by erasing the mark imprinted by the tagging device?

The answer, as it turns out, is that the interference pattern shows up again. Which, is , uh, weird. But again it gets weirder with the delayed-choice quantum eraser. Greene describes it thus,

It begins with [the set-up of the quantum eraser], modified by inserting two so-called down-converters, one on each pathway. Down-converters are devices that take one photon as input and produce two photons as output, each with half the energy (“down converted”) of the signal. One of the photons (called the signal photon) is directed along the path that the original would have followed toward the detector screen. The other photon produced by the down-converter (called the idler photon) is sent in a different direction altogether. On each run of the experiment we can determine which oath a signal photon takes to the screen by observing which down-converter spits out the idler photon partner. And once again, the ability to gleen which-path information about the signal photons– even though it is totally indirect, since we are not interacting with any signal photons at all– has the effect of preventing an interference pattern from forming.

OK, so far so good. This is just a fancier version of what we have already talked about, with the exception that we are now no longer causally interacting with the signal photon. Everything we know about the signal photon we learn by observing the idler photon. But even so, we get the photons acting like particles. But we aren’t done yet. Again Greene

 Now for the weirder part. What if we manipulate the experiment so as to make it impossible to determine from which down-converter a given idler photon emerged? What if, that is, we erase the which-path information embodied by the idler photon? Well, something amazing happens: even though we’ve done nothing directly to the signal photons, by erasing which-path information carried by their idler partners we can recover an interference pattern from the signal photons[!!!!!!]

OK, so what this seems to show is that it is not anything that we do to the photon that determines which way it will behave. Rather what determines this is whether or not we are able to know which path the photon takes to the detector. Nothing changes here except our ability to know which path the photon took.

We can hammer home this point with one further modification of the experiment. Suppose that we set it up so that we could only get which-path information from some of the photons (and further that which ones we get this information about is random). Again Greene.

Does this erasure of some of the which-path information– even though we have done nothing directly to the signal photons– mean that the interference effects are recovered? Indeed it does– but only for those signal photons whose idler photons [had their which-path information erased]…If we hook up equipment so that the screen displays a red dot for the position of each photon whose idler photons [had their which-path information erased] and a green dot for all others, someone who was color-blind would see no interference pattern, but everyone else would see that the red dots we arranded with bright and dark bands– an interference pattern.

So, it is the knowledge of which-path information that determines which way the photons behave. Since God always has which-path information, whether he obtains it in such a way as to effect the physical world or not, He will never see the interference pattern. Or in other words, the wave like nature of reality will be hidden from Him.

Sheez! That took longer than I thought!!  

God and Quantum Mechanics: Round Two

I was re-reading the comments on an earlier post where I proposed a dilemma for God’s knowledge of the nature of the reality. I argued that if God knows the outcome of the the random events hypothesized in (some interpretations of) quantum mechanics then his knoweldge of these outcomes will interfere with the physical process in such a way as to ‘hide’ the wave-like nature of matter. If this is the case then God’s knowledge is necessarily limited and we would have discovered something about nature that God can’t know (i.e. that matter has wave-like properties).

 In the comments the main response, given separately by Richard C. and Eric Weinberg, seemed to be that God’s knowledge would be achieved in such a way that it did NOT interfere with the physical process. It would not bring out the collapse of the wave-function and so His knowledge is not mysterious. I disagreed with this objection, but then I started thinking that even if I grant the objection there is still a problem here. So let’s grant it and assume that God knows the outcome of teh random physical process in such a way that it does not disturb the process and so does not collapse the wave-function.

 But if that is the case then we have the same, but opposite, problem that we had before. Instead of the wave-like nature of reality being ‘hidden’ from God, it now looks like it is the particle-like nature of reality that is ‘hidden’. For, if His knowledge does not collapse the wave-function then He won’t ever see the constituents of reality acting like particles!

Either way, it looks like we have discovered something about reality that God couldn’t have discovered on His own…

HOT (still) Implies PAM

In the comments on There’s Somethign About Jerry Josh and I have been having a nice discussion fo Rosenthal’s objection to my HOT implies PAM argument. The main challenge of my argument is a request to know what the difference is between conscious pains and conscious beliefs that results in there being something that it is like for the creature who has one but not when it has the other according to the higher-order theory. Whatever is offered it must be something that does not render the nature of qualitative properties mysterious and unexplainable. Josh’s suggestion is that the difference lies in the kind of property that one is attributing to oneself. As he says,

in the sensory [case], I attribute a state with such-and-such similarities and differences, arranged in such-and-such a mental space (space*) centered on me. The attribution of sensory qualities and mental spatial qualites, centered on the subject, makes it seem to me that I am in a sensory state. With intentional states, I do not attribute to myself this kind of thing; rather, I attribute to myself the property of believing that such-and-such is the case. No similarities and differences, no “egocentric” spatial stuff. So it will seem very different to me.

In my response I noted that I can agree that it will seem different to me, but it still remains a mystery as to how we get from ‘it’s different’ to ‘there is nothing that it’s like for me to have a belief’.

But as I was thinking about this I seddenly realized that this line of response fails for another reason (or, at least I can illustrate the reason on another way). So, mental states fall in four rough kinds for Rosenthal. There are sensations, perceptions (sensations+thought), thoughts (i.e. propositional attitudes), and emotions. The emotions, according to Rosenthal, do have intentional content, and so are propositional,

But it is equally plain[, he continues,] that the emotions are not just special cases of propositional attitudes, but are a distinctive type of mental state. What is it, then, that distinguishes the emotions fromt he cognitive states? Part of teh answer doubtless lies with the phenomenal feel that emotions exhibit. There is normally a particular way one feels when one is angry, joyful, jeleous, afraid, or sad, whereas the propsotional attitudes have no such phenomenal aspect. (C&M p 306)

Now when I am unconsciously angry there will be nothing that it is like for me to be angry, just like there will benothing that it is like for me to have an unconscious pain. When I am consciously angry I have a higher-order thought which attributes a qualitative mental attitude towrds some propsotional content (or state of affairs or whatever). So, I am conscious of myself as being angry that the guy in front of me won’t go when the light is green and then it is like being angry for me. So why is it the case that when I consciously believe that the guy in front of me won’t go when the light is green it isn’t like believing that for me? The difference between sensory qualities and beliefs isn’t present and yet there is still something that it is like for the creature (according to the theory)…so the difference that Josh and Rosenthal point to can’t be the difference that matters.