I don't know the answer to this question -- I mean the how question rather than the whether, for everyone dreams -- and it sounds (from the fact that he is resorting to words like 'presumably') like Andrew Pessin doesn't know either. For it's really a question for empirical psychologists, not philosophers, and the fact is that I haven't read their studies on the subject -- if, indeed, any such studies have been made. Even just anecdotal evidence should be treated with caution, and is likely to be little more reliable than armchair speculation. But, with that caveat, I am reminded of a talk I once heard from the philosopher, Elizabeth Anscombe, for she did have some anecdotal evidence to bring to the table here. She recalled speaking to a blind (though admittedly not deaf) friend of hers, and asking him what his dreams were like. She was naturally presuming that he would say something like, "I dream about how things sound, and feel, and taste, and smell." So she was a little surprised by the answer he...

According to the view that Berkeley is here criticising, there are, in effect, two worlds. Indeed, there are two corporeal worlds. There is an ideal world, constituted by perceptions that have been placed directly into our minds by God, and including perceivable tables, chairs, and even human bodies (including our own), complete with all of their familiar colours, textures, shapes, sizes and other sensible qualities. Then, distinct from and causally unrelated to this, and yet in some mysterious way corresponding to it, there is a world of material substances, including one that corresponds to our sensible body, but which cannot themselves be perceived, and which have no colours, no shapes, etc. Now, on this two-worlds view, how can we be so sure that our material bodies do survive? We can't perceive them, after all: how would we ever know? Maybe our material bodies got destroyed long ago: we'd be none the wiser, and it's not clear why we should even care, because God could perfectly well carry on...

I read the question rather differently: can any amount of past and present evidence falsify a claim about the future, insofar as it still remains the future ? Of course, past and present evidence can give us ample reason to doubt certain claims that might be made about the future: but could it ever demonstratively disprove such claims? I'm not at all sure that it could. An instance of an F that isn't G can falsify the proposition that all Fs are currently G, but it can't similarly falsify the proposition that all future Fs will be G. Current evidence tells us about what is currently true or false, and to project this onto the future for the purposes of falsification is as problematic -- no more so, but also no less so -- as projecting it onto the future for the purposes of verification. And, as David Hume showed us more than 250 years ago, that there are genuine grounds for concern about the latter. The 'problem of induction' suggests that there is a certain logical circularity in any ...

Well, there are several distinct points here, so let's take them one by one. I don't pretend to be an expert on those guys, but I have looked at them a little bit, and the impression I have is that, yes, they are philosophically rather naive. Indeed, that's the very reason why I've never bothered to study them in depth: because, compared to the works of more erudite and sophisticated philosophers, I tend to find their work a little dissatisfying. Being charitable, I suspect that part of this is down to the fact that they're deliberately writing for a popular audience, rather than an audience of trained philosophers, and consequently need to gloss over some of the more abstruse and nit-picking details. But such an explanation can only go so far. I think it's reasonable to suppose that many of them are simply unaware that some of these arguments -- both the theistic arguments that they're criticising, and the atheistic or agnostic arguments that they're supporting -- can be developed in much...

I've been racking my brains over this one -- it's a tricksy little question! -- and I'm still not sure what the answer should be. Of course Nicholas Smith would be correct, if the question was about the proposition that I am being systematically deceived. But it isn't. I take it that the question is how we know that it is possible that I am being systematically deceived. Admittedly, Descartes himself does ultimately conclude that this isn't even so much as possible: but he reaches this conclusion via a rather idiosyncratic and unconvincing argument, resting on the nature of God; and, in any case, even he acknowledges that it certainly does seem to be possible. He sets up his methodological scepticism in the First Meditation (as I'm sure you know), pointing to things like optical illusions, dreams, and the possibility of an evil demon. Many of the same points could be made about each of these arguments: but, for simplicity's sake, I shall just take the one about illusions. So, for...

I might just add one further observation here. At the risk of sounding pedantic, 'happiness' and 'sadness' are not adjectives (as you suggest). They're nouns. The corresponding adjectives here are the words 'happy' and 'sad'. Now, I would agree with you that there seems to be something deeply peculiar about a sentence like "this is happy brain tissue". Admittedly, and as Sean Greenberg indicates, philosophers don't tend to seek to reduce mental states simply to brain tissue but rather to states of that tissue. But still, that doesn't help: the sentence "this is a happy brain state" or "this brain state is happy" doesn't sound much less jarring. However, I think the reason why these sentences sound so harsh is not because we're here talking about a neurological state as opposed to a mental one. It would strike me as equally peculiar to say "this mental state is happy". That's because I disagree with your suggestion that we apply these adjectives to mental states at all. We do apply the ...

I'd be appalled if anyone was to suggest that there was something morally wrong about self-harm. Not least because the very worst thing that one could do to a cutter would be to make her feel even more guilty and ashamed than she probably already -- though quite undeservedly -- does feel. But is it in her own best interests to be cutting herself? In the moment, perhaps it can bring some fleeting relief from overwhelming psychological pain -- just as, in the moment, smoking can bring some fleeting relief from its own withdrawal symptoms. But, in the long run, smoking can lead to serious health problems; and habitual cutting can increase a sense of isolation and self-hatred, and generally tend to perpetuate the very psychological problems that led to it in the first place. Wouldn't it be nicer to be free of that emotional distress altogether, so that there'd no longer be any need to resort to such violent means to release it? Or at the very least, until that pain goes fully away, to develop some...

I have been hoping, and am still hoping, that others might chime in here, because I'm really curious to see everyone else post their own personal favourites. But here are a couple of mine. Hmm... am I required to think of sporting analogies? Sport is really not my forte. But I do remember a certain goal that a young David Beckham once scored for Manchester United, back in the mid-90s, with a single kick from behind the halfway line. I'd equate that with Edmund Gettier's 1963 paper, 'Is Justified True Belief Knowledge?'. Ever since Plato's Theaetetus , those who had wondered about such things at all had been largely satisfied that the answer was yes. (Ironically, Plato's own answer was no: but, as in many of his dialogues, he never offered a definitive solution at all, and the closest that we actually got to an analysis of the concept of knowledge was given along precisely these lines). No one ever seriously believed that truth, or belief, or justification for such belief, would be enough to...

I've nothing against Sean Greenberg's answer, but I figured I'd just add a word or two on a further relevant distinction here. Infinite divisibility is not the same as the possibility of dividing something into infinitely many parts. At least, it doesn't need to be understood in that way. There's a distinction that goes back at least as far as Aristotle, between the actual infinite and potential infinite, and the notion of infinite divisibility can be interpreted in either way. If we interpret infinite divisibility in the sense of the potential infinite (which, for what it's worth, is how Aristotle himself understood -- and endorsed -- the concept), this will mean that, no matter how small something might be, it can still be divided into still smaller parts. You can cut something into two halves, divide each of those to yield four quarters, divide each of these to yield eight eighths, and carry on going without ever needing to stop dividing. Mathematically, there is no greatest power of two: so, no...

Before I tackle your question head on, let me begin with an analogy: science. The number of philosophers who specialise in science is very small indeed. I'm not going to say that such people are non-existent: but, off-hand, I can't think of any. There are, however, quite a lot of philosophers who specialise in the philosophy of science. They ask very different questions from the scientists themselves, and they seek to answer them in very different ways. A scientist will seek to discover certain laws of nature that could explain how, as it might be, electrons cause certain observable effects to arise under certain conditions. But a philosopher of science will seek to analyse the very concept of a law of nature as such, or the nature of causation itself, or to describe what it actually means to explain something. Indeed, a philosopher of science might even question whether any amount of empirical data could ever justify us in regarding a scientist's claims about electrons as being literally true at...