Memory is not under one's direct control. (In this respect, it'slike belief: see Question 142 .) I can't force myself to forget what I hadfor breakfast yesterday. In fact, the more I try to do that, the morelikely it is I will remember what I had! Perhaps that does provide somekind of answer though: for the more one explicitly recalls a particularevent, the longer and better one remembers it. (At least, that's truefor me.) So, while one can't directly compel oneself to forget, one cando things that might make it more likely that one will forget, like nottalking or thinking about the event.

Why do you think inquiry into what happened in the past is anydifferent from inquiry about what's happening on the other side of theMoon? In both cases, we lack direct access to the facts. We must makeinferences, based on many assumptions, from what we do observe to whatactually was (or is) the case. Do you think history is differentbecause there's something different about the past? (We could inprinciple visit the other side of the Moon, but we simply cannot --barring time travel -- visit the past.) Or do you think history isdifferent because it focuses on the actions of people, and some kind ofdistortion always infects our reasoning about people that does not leadus astray in our inquiries into the natural world?

It's not easy to say what makes a definition right or wrong. There's a descriptive facet to it; for instance, if a dictionary were to define "apple" tomean "the fifth letter in the alphabet", they'd just be wrong becausethey'd be unfaithful to how that word is actually used. On the otherhand, there's a prescriptive facet to the task: dictionaryeditors don't write their entries based on a simple poll of speakers.It could be the case, after all, that many people are just wrong about what a word means. Butwhen politicians are debating about "what 'marriage' means" I don'tthink these fine points about semantics and what goes into a correctdefinition are usually uppermost in their minds. The topic of "what'marriage' means" is usually a euphemism for the question of what legalrights, economic advantages, and degree of approbation our society isprepared to bestow on gay couples.

You are a skeptic and yet you "have no doubt" that you had paranormal episodes? Hmmm. I'm not sure what else you believe, so I'll just talk about me. I've never had such an episode so having one would really be Big News for me. On the other hand, I have misplaced objects, often in ways that leave me completely baffled for a while. So, if I had what seemed like a paranormal episode, I think I'd go with the more conservative explanation. Makes life a bit duller than it might otherwise be but (a) this conservativeness in belief formation has served me (and others) very well over the long haul, and (b) life is exciting enough that it doesn't need that kind of boost.

Here are some reactions, each of which would require greater amplification and defense: 1) If psychology is a science, then it's results are not irrefutable. Science doesn't prove claims to be true in the way mathematics does. It's a fallible enterprise, and even its strongest results are advanced in the knowledge that they just might be wrong. 2) Quite a few philosophers are not impressed by what they consider bureaucratic boundaries and take themselves to be working on the same problems that psychologists are, perhaps at a slightly greater level of abstraction. They believe that their own work is really of a piece with psychological research: both constrained by it and simultaneously contributing to it. Their contributions don't usually consist in gathering data with which to test theories, but rather in the clarification and development of concepts or claims that figure in those theories. 3) Finally, some philosophers are skeptical that many of the most vexing philosophical problems about...

I suppose one could tell a story about the evolutionary advantage ofappreciating that "If a tiger is nearby, it's best to run" and "A tigeris nearby" together imply "It's best to run". Someone who doesn't graspthis inference is less likely to get down to the business ofprocreation than someone who does. (This isn't a justification of thisinference. Rather, I assumed the inference was correct and then offeredan evolutionary explanation based on that assumption for why humansmight find the inference compelling.) But logical inferences aren'thardwired in the sense that we have no choice at all about the kind oflogic we can adopt. See some of the responses to Question 168 fordiscussions of alternative logics.

For some relevant responses, see Question 241 .

Confession: I badly wanted to leave your question without an answer (hence making it not a question?)! Butit was too good a question. Or two good questions: (1) could there bequestions to which there are no answers? And (2) could there bequestions which have answers which we will never know? Ifyouthink that it makes sense to say that reality isn't always determinate,isn't always a particular way, then the answer to (1) would be Yes.There are some questions in mathematics, for instance, to which some(but not all)mathematicians believe there is no correct answer; the ContinuumHypothesis is a famous example. Some (but not all) physicists hold thatsomefeatures of the physical world are indeterminate as well, for instancethat there simply is no right answer to the question of what preciselyaparticle's position and velocity are at a particular moment. On theother hand, if you believe that if a question is fully meaningful, thenthe relevant reality it concerns must settle the matter one way or...

I think you're right that there is something inconsistent about theclaim that "X [some other claim held true] is the only truth". Thankfully, that's not what Descartesheld. He tried to show how all our knowledge (and he thought that weknew many truths) could ultimately be based on certain rock-solidstarting points. One of these was that I (understood asmy present thinking self) exist. This claim is not something that couldbe intelligibly doubted, he argued, because the very act of doubting itshows that it's correct. On the basis of this slimfoundation, Descartes attempted to erect the entire edifice of ourknowledge. For a modernized translation of Descartes' great Meditations on First Philosophy , see here .

You've made an important observation: explaining something bypostulating the existence of X doesn't take one far if the very samedemand for explanation can be raised about X. Philosophers like to tellthe story of the sage who was asked why the earth didn't fall throughthe heavens. He said: "Because it sits on the back of a giant turtle."His questioner was still a little puzzled and asked the sage what keptthe giant turtle from falling through the heavens. The sage answered:"Ah, you see it's turtles all the way down!" Obviously, turtles all theway down doesn't seem satisfactory. Of course, the sage might insteadhave replied: "This first giant turtle has no need of support!" But ifthat turtle has no need for support, then why not just say that theearth doesn't either? (This kind of argument is common in philosophy;for another application of it, see Question 127 .)