Saturday, December 22, 2007

Knowing what pains are like without ever having had one

The following principle is very plausible:
(*) One can only know what a pain is like if one has had a pain.
The principle is also plausible if one replaces "pain" with "pleasure", "auditory experience", "olfactory sensation", "pleasure", "a feeling of warmth", etc. However, (*) is false unless a certain version of disjunctivism is true. My argument for this shall apply to all the related principles as well.

Suppose we have Mary and Patricia. Mary is a neuroscientist who has never felt a pain. Patricia has had several physically painful, but non-traumatic, experiences in the past. She is not currently in pain. As long as Patricia remembers her painful experiences, we will say that Patricia knows what a pain is like. Moreover, let us suppose that it is not painful for Patricia to remember her painful experiences. It is typically painful to remember traumatic pains, and it is often painful to remember psychological pains, but it is often not painful to remember non-traumatic physical pains, and we can suppose that Patricia's are such. This supposition does not put into question Patricia's knowledge of what pain is like. We learn from these considerations that a version of (*) where "has had" is replaced with "is having" is very implausible.

Now, suppose that Mary implants in herself the memories of Patricia's painful experiences. If Patricia knows what pain is like on the basis of the memories, Mary should be able to know what pain is like on the basis of what she has just implanted in herself. Now, granted, what Mary has as a result of the memory implant are not strictly speaking memories, but apparent memories. If Patricia painfully fell of a bike at age 11, then Mary now has an apparent memory of painfully falling off a bike at age 11. But this memory is merely apparent because Mary did not in fact painfully fall of her bike at age 11. But it does not matter whether the memories be veridical or merely apparent for the knowledge of what pain is like. Mary knows that these are merely quasi-memories (to use Shoemaker's term), since she implanted them herself. But it seems plausible that they give her just as good an insight into what it would be like to have a pain as Patricia's genuine memories do.

Patricia knows by means of being able to see in memory what the experience of pain was like--without actually feeling the pain she is observing in memory. That the painful experience actually happened seems irrelevant to this, and if it is irrelevant to this, then it seems that Mary ought to be able to see in quasi-memory what the experience of pain was like. Subjectively speaking, after all, to remember and quasi-remember (or apparently remember) surely feels the same.

There is an objection to this argument, namely disjunctivism. If experiences feel differently depending on whether they are veridical or not (Ram Neta defends this view), then Patricia's memory and Mary's quasi-memory may not be similar enough for Mary to be able to know what the pain was like. But a disjunctivism about memory does not seem deeply plausible. Our memories are often foggy even when veridical. That they really do feel different when they are veridical does not appear all that plausible to me. But I have no solid argument against this disjunctivist thesis, and hence all I can say is that if this kind of disjunctivism is false, then one can know what pains are like without having had any.

Note: If the mental locally supervenes on the physical (at least for humans), Mary doesn't even need Patricia for this. She can just run a computer simulation of her brain, body and environment to figure out what her neural memory-correlate state (i.e., the neural state correlated with the memory of the event) would be several years after herself painfully falling off a bicycle, and then implant that neural state in herself.

Related question: Can God, without making use of the Incarnation, know what pains are like? The main reason to deny that apart from the Incarnation, God can know what pains are like is something like (*), combined with a claim that God doesn't feel pain qua God. My above argument, however, shows that (*) is probably false. And this undercuts the main reason for denying that God knows what pains are like. If one could show that my counterexample to (*) is the only kind there can be--so one must either be in pain or have a memory of pain or have a quasi-memory of pain to know what a pain is like--then one could rescue the argument against the possibility of God knowing what pains are like, since divine perfection is incompatible with non-veridical quasi-memories.


Richard Beck said...

Hi Alexander,
Thanks for continuing the conversation. And I'm very pleased to have found your blog! I've enjoyed my internet conversations with Keith DeRose from Yale.

I once heard that the art of philosophical disputation is to recast your opponent's argument in such a way to make it obviously false. I hope I don't do this with you. Any crudity on my part in framing your argument is due to that fact that I'm a psychologist and not a philosopher. Help correct me when I make a mistake.

For myself, I want to try to clarify which of the following propositions you claim to either accept or reject as consistent with this post. For the memory transplant case I'd like to use the experience of the color red.

Which of the following (again, I'm not trying to box you in, just trying to clarify) is what you are arguing for as possible:

#1: You can have a visual memory of red without actually experiencing (subjectively speaking) the sensation of red.

#2: You can have a visual memory of red but this visual memory would (subjectively speaking) recreate (in an impoverished way) a part of the experience of red.

Referring back to my post, if you endorse #1 then I feel comfortable with my position. That is, this "non-sensory memory" might be transplantable but the subjective facet--the part I'm interested in--has not been transplanted.

If you endorse #2 then the subjective experience is recreated--via transplant and the subsequent activation of the of the sensory cortex--in the mind of another person. Again, I feel comfortable with this position. A subjective experience can only be known if that experience is "felt" (how this occurs is irrelevant for my purposes) within one's own subjective field.

I may have misunderstood, so any clarifications and rejoinders are welcomed.

Alexander R Pruss said...


Let me first try to sidestep your excellent question.

It seems to me that we would say that Patricia, who has seen red things often, knows what it is like to see red, and that she knows this even while she is not occurrently remembering or currently seeing red. (It surely isn't right to say that while she is looking at green grass, and not thinking about anything red, she doesn't know what it is like to see red.) And if Patricia knows this without occurrently remembering or currently seeing red, then Mary knows it, too, after she gets the memory transplant, even while she is not occurrently quasi-remembering red.

But maybe the interest is not in this kind of knowing, but in something more occurrent. And if so, then I can't side-step your question. I don't actually know whether visual memories of red things involve the actual re-experiencing of red. Maybe. But even if so, I don't think this is true for all experiences. For instance, for me, the only visual memories I have of steadily bright objects do not involve a steady brightness--somehow, all my visual memories are kind of faint in color, and if they have brightness, it is in flashes, not steadily.

Also, I don't think that a memory of what a pain was like is necessarily a painful memory. So at least for some qualia, like those of physical pain, it is possible to have a memory of what that experience was like without the occurrent remembering being a re-experiencing.

I do hesitate about red. My visual memories of red things kind of seem reddish. But I think that they may be reddish in a somewhat different sense from the reddishness we see with our eyes. But I don't know for sure.

Here's an interesting question. Take the following four experiences:
1. Seeing a red cube.
2. Dreaming of a red cube.
3. Remembering seeing a red cube.
4. Remembering dreaming of a red cube.
Which, if any, pairs of these experiences share the same quale? I really don't know...

I am inclined to think that (3) and (4) share the same phenomenal character vis-a-vis redness. It is quite possible to remember a visual image, and not be sure if one has seen it in reality or in a dream.

There is some plausibility in thinking that (1) and (2) share the same phenomenal character. After all, we can be unsure whether something is a dream or reality.

And there is some plausibility in thinking that (2) and (3) share the same phenomenal character. Here, the data is not so much introspective, as based on some theoretical notion that dreams are built up out of the stuff of memories, and so we would expect similarity between the subjective experience of remembering and the subjective experience of dreaming.

But if we accept all of this, then we conclude that (1) and (3) share the same phenomenal character, and then we have your option #2, which undercuts my argument in the case of red (it might still survive in the case of pain).

I would question whether (1) and (2) involve the same phenomenal character. That we can confuse dreams with reality does not mean that they look the same. It is possible to misidentify an object as an object that in fact looks very different if one is in a suboptimal mental state, and when we're dreaming, we're in a suboptimal mental state.

I would also question whether (2) and (3) involve the same phenomenal character.

But maybe you can say the following. Although it is not necessary to be having a subjective experience of red to know what it is like to see red (at least in some occurrent sense of "know"), it is necessary to be having a subjective experience of some sort. We can, after all, sometimes derive from knowing what one type of experience is like what another type of experience would be like. (Thus, we can know what the experience of seeing a live unicorn would be like, though we've never had that experience.) Perhaps, then, my example simply shows that we can know what the experience of seeing red or feeling pain is like on the basis of the different but related experience of remembering seeing red and feeling pain, respectively.

Relevant here is Hume's example of the missing shade of blue. The idea was that if there was a shade of blue you never saw, but you were looking at a spectrum with that shade missing, you could know from your experiences of the neighboring shades what the missing shade would look like to you. That seems right. Maybe just as you can tell from neighboring shades what the relevant shade would look like, so too you can tell from rememberings what the remembered thing was like.

If so, then my argument wouldn't endanger the bigger point that a being that has no subjective experiences can't know what it's like to have subjective experiences. Unless, of course, we can get by with a non-occurrent sense of "know", in which case the first argument in this comment applies.