It has been suggested that the practice of Bonsai is an expression of animal chauvinism and does great harm to a tree by 'stunting' it. But aren't trees not sentient beings, and therefore the excising of branches, shoots and roots such that the tree thrives albeit substantially smaller than its genetic potential, is no different to the continual loss of roots, shoots and branches that occur under natural conditions?

There is the fact that it is possible to treat something badly or to damage it, whether or not it is sentient. A pair of shoes can be badly or well looked after, and it is wrong not to look after a good pair of shoes properly. A living thing like a hedge can be properly maintained or attended to, but something more is involved. Sometimes, it seems to me, the aesthetics of the "art object" (horrible phrase) can reflect what it actually is. So it is natural to trim a box hedge in one way, and a mixed hedge in another way, perhaps a less formal and more undulating, the shapes reflecting the different kinds of growth - hawthorn, or privet or beech. (A hedge that is full of straggly and unwanted sycamore looks awful, and the holes soon begin to show.) Pugs and poodles may be perfectly happy qua sentient beings, though often there are specific health problems with specific breeds, but it is perfectly coherent to object to the whole process of breeding and thinking of living things as being objects for our use ...

Is it wrong to lie when we're questioned on matters of our intimacy? I mean cases where the other reasonable option would be to refuse to answer but for some reason we prefer not to. More specifically, I mean cases where it was wrong to ask in the first place.

'[I]n general truth-telling is morally preferable to lying . . .', Peter Fosl writes. This doesn't seem quite right. Lying is wrong , and telling the truth is right , not just a bit "morally preferable", even if there are worse things than lying. There seem to be too many ways of avoiding or deflecting the question to make it seem plausible to say that one has to respond, morally speaking, by saying something. Why not simply ignore the question? That might be rude, or even a bit cold, but it's better than telling a lie, surely.

What does it mean to exist?

Are you content with the question as you have formed it? What does it mean to exist? Compare: What does it mean to garden? What does it mean to play chess? What does it mean to help someone in need? What does it mean to suffer? What does it mean to kill someone? Compare the last question with the even more serious, 'What does it really mean to kill someone?' One can perhaps accept this as a question without knowing what its full import is. Perhaps it is a desperate expression of remorse and the wish to make amends. But this cannot be true of 'What is the meaning of gardening?' unless it means something tame, though not therefore unimportant, like, 'How does gardening contribute to your life?' Or perhaps you believe that you have wasted your life gardening, and you are now reflecting on this sad fact, if it is one. It seems to me, without complete conviction, that the six questions shouldn't be attacked head-on. It really is pretty unclear what they mean and how...

We can only live in this "here&now moment" fact, there is no way we can ever live out of "IT" it not?

'We can only live in this "here and now" moment . . . in fact , there is no way we can ever live out of it . . . is it not?' I am not sure what is supposed to meant by living in the present instant ("moment" I think has more to do with action). Living at an instant seems as impossible as living at some other time, because there isn't even time to draw breath in an instant. In any case I do not believe that there is something called "the present instant", so I don't see how we could live in it (at it?) It (the present instant) is an abstraction, and it is not, in reality! I do believe there are present times, though, such as the present day or hour. The trouble with the instant is that it is not a time.

How can I hear my voice in my head without speaking?

"How can I hear my voice when I'm not speaking?" is your question. If we reserve the word "hearing" for what the ears do, and "the voice" for what the mouth speaks - not unreasonable, I think - then your question becomes, "How can I "hear" my "voice" when I'm not speaking?" i.e. "How can I undergo something which seems rather like hearing ("hear", in an extended or perhaps metaphorical sense) something which seems rather like my voice ("my voice", taken in an extended or perhaps metaphorical sense)? The important thing is to try to get clear about what the metaphors are metaphors on , if I can put it this way. ("The sun" is a metaphor on Juliet.) It is more than just imagination, because I can imagine a voice speaking, and hear it, without imagining that I hear it. That is, the minute the voice "speaks", I "hear" it, without an added act of imagination of the auditory (or rather, "atidory") kind. That is a puzzle: direct realism about inner "voices"! To the wider question, though, it is helpful to...

I am a philosophy student that doubts philosophers; I can't write papers, or at least trying to make the connections emerge from details is damn near the hardest thing I've ever done. I have the right ideas (that I am sure of) and I can talk philosophy (intersbujective exp. confirms this) but my papers fall into detail etc. (No one has ever said, WOAH this paper should be published). But even when, one night, I curse the very subject matter and damn it all to hell, I wake up the next morning prepared to try again. But still, at night I try to cast the dead weight from my shoulders in despair. Question: if one's temperament is philosophic should they steer away from academic philosophy? Question 2: Should the person who falls in love with wisdom only to damn her at night continue to make the effort, indeed, should one rule out a life-long marriage with the enticing specimen?

Answer to Q1: Why should a person who loves philosophy not steer towards academic philosophy? The better one knows her the more she has to offer, such as fascinating arguments. Answer to Question 2: If you are in love with someone, you really should marry that person, other things equal, no? Philosophy can be difficult sometimes, even temperamental, but she is not mad .

Although they cannot pretend to have "solved" the problem of induction, scientists have no qualms whatsoever about making inductive inferences in their work. Likewise, I take it that judges and lawyers agree that murder is a terrible crime, even if they are at a loss to explain why one's death is a harm to one. Why is it that we feel totally comfortable in going about the various activities of human life, even when there are (seemingly) gaping holes in the philosophical theories which are supposed to underwrite or justify those activities?

It is not obvious to me that we - we philosophers, that is - do feel totally comfortable about the activities of human life. We worry about induction, whether death is an evil because it deprives us of some good, and so on. But there is no absolute requirement to worry, and most people don't. And that is perfectly rational. In just the same way, I am not worried at all about the fact that I have no idea why gravity works. I can walk happily about on the surface of the earth without really understanding why I don't fly off it. Physics is a specialist activity that most people don't need. We don't have to understand too much of it to go about our daily lives without a lot of intellectual discomfort. But we can if we want, or we can try to!

How does our approach to knowledge about the past differ from our approach to knowledge about the future, keeping in mind that there is an element of uncertainty in both?

Our knowledge of the past derives from perception, memory and inference, in the sense that these are answers to the question, 'How or by what means do you know?' (There are other ways, for example report or testimony). But our knowledge of the future has in it no elements of memory or perception. So as one might therefore expect it is harder to come by knowledge of the future, and we have less of it per hour, if you want. We typically can know more about a past hour than about a future hour, though by no means all of the past hours, for example those in past centuries. If I know p, and p is a proposition about the future, I cannot know it by memory, special cases apart. (A special case would be that I come to know that I am going to Africa next summer - a piece of knowledge about the future - by remembering that I am going to Africa next summer. 'How do you know?' 'I just remembered it . . .' makes sense as a conversation.) It seems to me, in spite of the assumption you make, however, that in some...

I have always thought that with the primary colors and black and white, you can create any color that we see. This may sound dumb, but then how do you make neon colors? What else can you add other than the previously mentioned colors (or lack of)?

Do you think that colours emitted by neon gas have a particular neon quality? I'm not sure. But your question could very well be asked of the metallic colours, such as silver and gold. They are not "made" by any combination of primaries, so how are they made?

The visible spectrum of light starts at red and moves to violet. Wavelengths of E.M. radiation slightly longer than red are infra-red and shorter than violet are ultra-violet, neither of which is visible to humans. My question is then: why do we see the spectrum of visible color as a cycle moving seamlessly from red to violet and through violet into red again (think of a color wheel)? Why do we not see the visible spectrum the way it would seem to make the most sense, i.e., fading in from invisible infra-red and fading out to invisible ultra-violet? This has been bugging me for some time now, hopefully one of the panelists here can give me a satisfactory answer or point me in the right direction. Thanks, -Liam C.

The fact is that the correspondence between colour and frequency is rough and approximate. To some "colours" (and what does this mean?) there corresponds no wavelength, or no single wavelength, of monochromatic light. Examples are the browns, the appropriately named "non-spectral" purples, and white. (Black is also an example!) The colours form a circle (roughly) or a three-dimensional solid of which the circle is a cross-section at middle brightness in fixed illumination. This is colour space; and the frequency scale does not really model its overal complexity, except around the one corner at the edge: the spectrum. This is related to the fact that there are three types of cone which respond to coloured light, not four. There is no photoreceptor which peaks in the yellow, so when we see yellow it is the "red" and "green" cones that are being stimulated. Scientists tend to draw the conclusion that "colour is a sensation", as Maxwell put it. But this can't be right, as I see it, for the most part for the...