I'm sympathetic to most of what Professor Heck says, if we consider things from a deontological or even a consequentialist point of view, where the relevant consequences are external to the agent. Fantasy does not violate anyone's rights, and fantasy that never motivates action will not result in actions that harm anyone. But I think there is a plausible way of looking at things that would still find fault with fantasizing about having sex with children, and that would come from the aretaic (or virtue-theoretic) way of thinking, according to which the primary bearer of value is to be found in characteristics of agents. One who indulges in fantasies about sex with children is doing something that both reflects--and also perhaps perpetuates and sustains--a certain trait of character that we might think is not entirely wholesome or admirable. To the extent that we can regard one who indulges in such fantasies as having a trait of character that is improvable, we might also think that some attempt to eliminate or at least diminish the inclination to indulge in such fantasies would result in that person having some improvement in character. It may be that habituation can only go so far, and that virtue theorists (such as Aristotle) overrate the extent to which one can habituate better character traits, but it certainly does seem that a virtue theorist could find the character of someone who tends to indulge in such fantasies at least improvable, and this way of looking at things does, I think, put a different face on this kind of case than what Professor Heck has indicated.
Your question raises what is known as the "de dicto/de re" distinction. Rather than give a formal explanation of that (for which, have a look at the Stanford Encyclopedia of Philosophy), I'll try to put an answer without using the distinction explicitly.
One way we can think about intentions is to think that an intention is at least partly contituted by the specific content in which the intention would be expressed. Hence, when Oedipus killed the man where three roads met, his intention was not to "kill his father" (or, for that matter, to "kill Laius"), but to "kill the SOB who has the gall to push me--the crown prince of Corinth--aside"). In other words, if you asked Oedipus, "What is your intention?" he would surely not sincerely reply in terms off anything having to do with his father. On the other hand, it is also true that there is another sense in which he intended to kill his father, since he intended to kill that man, and that man = his father. But I think if we were reporting his intentions, it would be somewhat misleading to describe his actions as "intended to kill his father," and so the first sense is the one that would be more appropriate (for example, if we were testifying at a trial).
Certainly consulting a physician is a good idea. There is a smattering of knowledge of some of the brain chemistry underlying some forms of depression and anti-depressants do work for some people. A physician might be able to offer some advice about different forms of therapy, such as CBT which is now popular. In any event also look into other forms of therapy, ask around, look on the net. If you are on facebook go to Depressives Anonymous and ask your question there, where you will probably get several informed responses and will be able to discuss your problem in more detail. Meantime try to do stuff you enjoy, try not to worry and chill out as well as you can.
There are broad differences between ethnic and cultural groups that have to do with the ways in which people are socialized into those groups. But to understand these artifacts of culture as differences in psychology seems to me to be a mistake. Anyone who has had any kind of rich interaction with different members of such groups will know well just how hugely varied people are. But enculturation does have effects, of course.
A bad person is one who is inclined to act in bad ways. A mentally ill person, accordingly, can also be a bad person. We might think of a mentally ill person as someone who simply can't help doing what they do--where those who are not mentally ill can actually make real decisions. But just because I can't help doing something terrible doesn't make it not terrible when I do it.
But I doubt that the expression "mentally ill" is one that iss very clear-cut or well conceived. Plainly, there is something wrong with anyone who acts badly--just exactly what is wrong with them (whether some "mental illness" we now have a name for, or just a lousy background, or poor education in values, or ...) may be somewhat unclear to discern, aand the border between "illness" and other factors may get extremely blurry. My guess is that the more we know about the brain, the more we are going to find out that "mental illness" will be replaced in our descriptions of the world with several other options that make what is actually wrong in various cases much clearer.
I'm not aware of any philosophical uses of this phenomenon. I myself would be inclined to think that unless we can show that these experiences are veridical (in other words, if by some scientific process, we could show that those who experience deja vu actually were "there before"), we should not count them as evidence for anything other than the (obviously true) claim that many human intuitions and experiences can be highly unreliable, and so we should be extremely cautious about which of these we allow to count as evidence for or against anything.
I don't understand your friend's answer any better than you do, so I'm afraid I can't help you on that one! As for the Chinese Room, the case as I understand it is supposed to show that something could pass the Turing test--that is, it could provide correct outputs to given inputs--without understanding/intelligence. A string of Chinese symbols would go into the box, and the one inside (knowing no Chinese, but simply guided by the shapes of the characters in the input) would simply match these mechanically to others in a pre-established list, which he would then send out again. To the one reading the outputs (one who knows Chinese), it would look as if the outputs were the result of understanding...but they would not be. Hence, passing the Turning test for knowledge of Chinese would be no indication of actually understanding Chinese, and so the test is itself inadequate.
I'm not quite ready to accept your terminology, but will try to respond in spite of that. I think the most obvious difference between ordinary perception and things like hallucinations and dreams is that the former sorts of experiences are reasonably assumed to be verific (that is, to tell us something true about the world), whereas the others are not verific, or at least are only very unreliably so. The fact that I dream that such and such is the case (assuming I have no reason to think that I am some kind of dream clairvoyant) is of course compatible with it really being the case...but gives me no grounds for believing that it really is the case. The fact that I perceive something to be the case does give me grounds for believing that it is the case. I am not claiming, of course, that perception is infallible, for it plainly is not. What I am claiming is that there is evidenciary value in perception that is lacking in hallucination, fantasy, dreaming, and other such experiences.
It really depends upon what you mean by "element" or "energy source." If you mean by these what these terms mean as they are used in contemporary science, then at least in principle we could understand and explicate thoughts and thinking wholly in the terms of contemporary natural science. But there are a number of reasons philosophers have given for doubting that a full explanation of thoughts and thinking can be given in such terms. Let me just mention a few:
The problem of qualitative content or qualia: Thoughts have aspects that seem as if they would, in principle, resist wholly physicalistic explanation--for example, the experiential properties of what it is like to have such thoughts. Conscious beings who are thinking understand that the experience of thinking is a certain kind of experience--different, for example, from the experience of having an itch or the experience of being about to sneeze. Even if we can correlate these experiences with certain states of the brain, it is correlation only--not identity--as biochemical states do not of themselves include experiential properties.
The problem of privacy: My thoughts are in me; your thoughts are in you. Even if we agree about something, my thoughts themselves are not accessible to, or observable by, you. You might in principle observe my physical states (energy or elements); but it doesn't seem that you can observe thoughts.
The problem of ownership: My thoughts are mine; your thoughts are yours. Elements and energy sources can go from one system to another. My thoughts cannot become your thoughts (even if, as I am now trying to do) I can get you to think something that has the same content as what I am thinking. Yours will still be yours; mine will still be mine.
The problem of intensionality: This is a difficult one to explain very briefly, but I'll try. Thoughts have a peculiar logical property--when we say what the actual content of a thought is, we cannot "substitute equals for equals," as it were. So, I might think that Muhammed Ali is the greatest boxer of all time. But I might not think that the boxer who defeated George Foreman in a title fight in Zaire is the greatest boxer of all time. (I might suppose that Joe Frasier fought in and won that fight.) But of course, Muhammed Ali is the fighter who defeated Foreman in that fight. So just because Muhammed Ali = the fighter who defeated Foreman in Zaire, you will not describe my thought that Ali is the greatest if you substitute "fighter who defeater Foreman in Zaire" for "Ali" in describing my thought. The two expressions refer to the very same man (Ali), but only one can be used to describe my thought. Even if I actually knew that Ali defeated Foreman in Zaire, the thought that the boxer who defeated Foreman in Zaire is the greatest boxer of all time is a different thought than the thought that Muhammed Ali is the greatest boxer of all time, because it has different content. So, philosophers say that the contents of thought exhibit a logical property (of non-substitutivity, as well as other features) called intentionality. Scientific descriptions of things like elements or energy sources do not seem to exhibit this property--substitutivity seems to hold in such descriptions.
For these reasons (and others I have heard), many philosophers doubt that thoughts and thinking could ever be understood wholly in terms of elements or energy sources, at least as these are presently understood.
These same considerations, by the way, have led some philosophers (those most impressed by scientific knowledge as it is now configured) to propose that such terms as "thoughts" and "thinking" are really just "folk psychological language," which we would do well to jettison, because they bring in mysterious and what they regard as bogus features such as those I mentioned above. In other words, the very fact that "thoughts" have intentional features is a good reason for thinking there are no such things as "thoughts"! I leave it to you to decide what to think about such a proposal! ;)