This is a really interesting question. John Locke, in his Essay Concerning Human Understanding, famously defined a person as "a thinking intelligent being, that has reason and reflection, and can consider itself as itself, the same thinking thing, in different times and places; which it does only by that consciousness which is inseparable from thinking, and as it seems to me, essential to it." He then goes on to talk about our personal identity over time: "For, since consicousness always accompanies thinking, and it is that that makes everyone to be what he calls self, and thereby distinguishes himself from all other thinking things, in this alone consists personal identity, i.e., the sameness of rational being; and as far back as this consciousness can be extended backwards to any past action or though, so far reaches the identity of that person." The notion of consciousness extending backward is often taken to signify memory, and so a Lockean theory of personal identity suggests...

After reading this question, I first tried to transmit my answer to you telepathically, but it wasn't working, so I thought I'd try this more traditional method. In any case, it strikes me that in order for something to count as telepathy, one would have to have some sort of direct and unmediated access to the thoughts of another. Suppose Jane and Clone Jane both go see a movie and, because they have identical genetic makeups and (let's suppose) similar past experiences, they each think something like "The ending would have been more emotionally satisfactory had the hero not gotten killed." Each of them is having the thought for the same reason, but they are each having it independently. That is, Jane's thought has no causal connection to Clone Jane's thought, and Jane does not have any direct access to Clone Jane's thought. And vice versa/ Their thoughts have similar (parallel) explanations, but no direct linkage to one another. So I don't see why this should count as a form of telepathy. ...

In my view, experienced pain still counts as pain, even if it is not later remembered. The key here is that the pain was actually at one time experienced . Some kinds of anesthetics block pain experience altogether -- for example, when pregnant women have c-sections, they typically do not experience the pain while the procedure is going on and the anesthetic is in effect. (After the anesthetic wears off, well, that's another story altogether...) In contrast, you describe a different kind of anesthetic, one that does not stop the pain from being experienced, but just stops it from being later remembered. And I would say that unremembered pain is still clearly pain. Here's one way to think about it. Suppose that right now, while fully conscious, you were offered a deal: If you agree right now to be tortured, you will get $10,000. You will be in extreme agony for an hour, but afterward, the torturer will give you a drug to make you forget the torture entirely (and you will get your $10K). ...

The prospect of going under anesthesia is a scary one, for all sorts of reasons. But I don't think you should have much cause to worry about identity issues. I have two comments that might help alleviate your concerns. First, you might ask yourself: What would be the difference between its being you who wakes up from the anesthesia and its being a doppelganger with your memories? From the outside, you would seem exactly the same. And from the inside, it would seem the same too. Your doppelganger might be thinking something like this: "Yesterday I was worried about whether I would wake up from the anesthesia, and I'm glad that my worries were for naught -- here I am." In other words, the prospect that you're proposing is not really one that can be discerned -- either from the inside or from the outside -- as one that makes any difference to anything. But if that doesn't help (and I'm a bit worried that it won't), it might better reassure you if you think about anesthesia on the...

Hmmm... did you submit your question via the new iPhone app by any chance? I ask because some philosophers have recently argued that the way that we use certain tools, like iPhones for example, extends our cognitive processing, and thus the mind, out into the world. Is there really a difference between the memories we store in our brains and the "memories" we store in external devices? When someone on the street asks you whether you know the time, you might answer affirmatively even though you have to consult your watch (or your phone) to tell them what time it is. You know the time in the sense that it is accessible to you. Likewise for the contacts that you have committed to iPhone memory rather than biological memory. Were someone to have a memory chip implanted in her brain, we might well accept that as part of the mind even though it is nonbiological. But why should it matter whether the chip is implanted in the brain. Couldn't it function the same way if it were outside the brain,...

You might want to take a look at some of the recent work of John Searle, such as The Rediscovery of the Mind . Searle argues there that "The notion of an unconscious mental states implies accessibility to consciousness. We have no notion of the unconscious except as that which is potentially conscious." (p. 152). While this isn't quite an endorsement of what you call the "transparency thesis," I believe it might be seen as a quasi-descendant of the view you describe. As an aside, the name "the transparency thesis" is nowadays often used by philosophers of mind to refer to quite a different phenomenon, namely, that when we introspect our experience, we don't seem to be able to attend directly to it; rather, our attention seems to slide right through to the objects of our experience.

I think it is easy to imagine things that you are presently doing that you don't realize that you are presently doing, as in Peter's Luxembourg example, above. More interesting is whether you can imagine things that you do realize that you are presently doing. Peter's example of the naked supermarket shopper, also above, is underdescribed in this way -- does the absentminded philosopher know he's naked in the supermarket when he's imagining it? If you are inclined to think that you can't imagine something that you know you are presently doing, then to make sense of the naked supermarket shopper case you might have to think of it this way: Professor McAbsentminded heads out of his house, unaware that he is naked, and unaware that he ends up in the grocery store. While he is then -- unbeknownest to himself -- standing naked in the grocery store, he imagines himself standing naked in the grocery store. I'm not inclined to put this restriction on imagining, however. I think we can...

Many philosophers would say that you couldn't. This relates to Jackson's famous Mary case (previously discussed here - and originally laid out in Jackson's article "Epiphenomenal Qualia." ) Jackson asks us to suppose that Mary is a color scientist who has spent her entire life in a black and white room. Though she has learned all the physical science relating to color, she has never experienced color herself. Now imagine that one day she is let out of the room and shown a ripe tomato. Jackson supposes that we would have the intuition that she has now learned something new about color. "Aha," she might say to herself, "So that's what the color red looks like." In other words, despite knowing all the physical facts about color, Mary did not know what it is like to experience the color red. If you buy this argument, then it would seem to follow that even if you were to teach the blind child (who, I'm assuming, is blind from birth) all the physical science about the color green, you still...

Let's separate two questions. One is the question of whether there could be beings with mental lives far different from our own, who process the world far differently from the way we do, and with whom we can't presently communicate. I am inclined to answer that question "yes." Perhaps we are already familiar with such creatures. (Dolphins? So long and thanks for all the fish.) The second is the question of whether human beings who are radically deprived of any early sensory stimuli and whose brains thus fail to develop normally nonetheless have complex thoughts that they are just unable to communicate to us. Here I am inclined to answer "no."

There was a real life case of a girl named Genie (a pseudonym) who was deprived of any real sensory stimuli for much of her young life because of the abuse of her father. Her story is told in a book called Genie by Russ Rymer. Her case suggests, in line with what Alex says above, that the absence of early senory stimuli prevents a human being from developing a normal mental life.