Derek Parfit's Reasons and Persons is a long, difficult and fascinating book, inside which three shorter, clearer and better books are struggling to get out. The third of these shorter but better books deals with the problem of Future Generations, and that is the book I want to discuss. In it Parfit tries, but fails, to find a theory—Theory X, he calls it—which will deal with various problems and issues which he develops, and in particular the issue which I will call the Parfit Population Problem, the problem of how many people there ought to be. In this paper I offer not so much a theory as a suggestion as to what the solution(s) might be.

There is a tradition of philosophy—a conception we can easily under-stand as a limit of a tendency of our own thinking—that philosophy consists only of argument. The rest of the (admittedly) vast prepon-derance of words in philosophical texts is simply embroidery. ‘Naturally’, it will be conceded, actual philosophy books contain more or less of verbal pictures, words and phrases whose purpose is to evoke images, and many stories—examples, hard cases for definitions, and 4 anecdotes. These, it will be said, ‘are only the embellishments, the relief from work, the appetizers or the post-prandial delicacies.’

Various proponents of animal rights—for example, H. J. McCloskey— maintain that while brute animals (henceforth ‘animals’) cannot have; moral rights they can have legal rights. Indeed, McCloskey himself goes so far as to maintain that even inanimate objects are able to have legal rights.1 And why should not inanimate objects be able to? After f all, for there to be a legal right is anything more required than that whatever agency is empowered to issue legal rights simply legislate or proclaim that so-and-so has that legal right?

In his paper ‘A Function for Thought Experiments’, T. S. Kuhn asks: Ought we demand of our concepts, as we do of our laws and theories, that they be applicable to any and every situation that might conceivably arise in any possible world? Is it not sufficient to demand of a concept, as we do of a law or theory, that it be unequivocally applicable in every situation which we expect ever to encounter?

‘The past is a foreign country: they do things differently there.’

On a hot sleepy summer day an old truck rattles along a dusty road. A turnip falls off the truck, the truck does not stop. Perhaps the old man who drives the truck does not know that the turnip fell off, or perhaps he does not care. He values his time or his ease more than he values the I turnip. We, who know not only that turnips are nourishing but that many people go hungry, may say that the man ought to have stopped to pick up the turnip.

In Plato's dialogue the Euthyphro, Socrates poses a question that has come to be known as the ‘Euthyphro dilemma’. Since the first formulation of this problem is surely the best, I will quote from Socrates himself:

… For consider: is the holy loved by the gods because it is holy? Or is it holy because it is loved by the gods?

Should I have the opportunity to travel back in time to converse with great philosophers, Hume would be high on my itinerary. My gratitude for his insights and hospitality would surely tempt me to reciprocate by telling him about my time travels. But I fear he would not believe me. For the reasoning underlying Hume's famous scepticism about miracles dooms my tales of time travel to an incredulous reception. The ensuing paragraphs will be dedicated to an elucidation of this fear. This elucidation is of more than historical interest, since Hume's reasoning about miracles still strikes many contemporary philosophers y as cogent. Thus the scepticism about time travel that I attribute to Hume should also be shared by his followers. It should be noted that the scepticism at issue is epistemological rather than metaphysical. The key question will not be ‘Is time travel possible?’ We shall instead ask whether it is possible to justify a belief in a report of time travel. The metaphysical issue will only be addressed in response to the question of whether one can be an epistemological sceptic about time travel without being a metaphysical sceptic.

In her paper ‘Is it True What They Say About Tarski?’, Susan Haack argues that Popper is wrong to regard Tarski's theory of truth as a correspondence theory of truth. For, she says:

… Tarksi does not present his theory as a correspondence theory. In fact Tarski explicitly comments that the correspondence theory cannot be considered a satisfactory definition of truth. And later he observes that he was ‘by no means surprised’ to learn that, in a survey carried out by Naess, only 15 per cent agreed that truth is correspondence with reality, while 90 per cent agreed that ‘It is snowing’ is true if and only if it is snowing (p. 324).