Poetry, W.H. Auden famously and provocatively wrote, makes nothing happen. The same might be said of philosophy. It all depends, of course, on what we take "nothing" to signify. Philosophy certainly will not crack for us the fundamental mystery of being, which is nicely summed up in Leibniz's question, "Why is there something, rather than nothing?" (When I cited this question once before in a review, I received a letter from a mathematician accompanied by a number of closely-printed pages of calculations to show me exactly why there is something rather than nothing; I am still no wiser.)
The story goes that in a taxi once Bertrand Russell was recognised by the driver, who at a red light turned to him and asked: "So, Mr Russell, what's it all mean, then?" Russell's reply is not recorded.
Some weeks ago in these pages I quoted the logical positivist A.J. Ayer as a young man declaring that on one side there is philosophy, and on the other, "all this - all of life!" A great many professional philosophers would agree; theirs, they will claim, is a closed world, and rightly so. Philosophy aims to address and if possible answer a certain set of difficult but well-defined problems. Any discoveries made along the way will not make a jot of difference to the way the world is or the way we live in it, and mostly will feed back into the ongoing search for basic truths - basic to the discipline, that is, but not necessarily to life. It is as if a sawmill were to use the wood it produces as fuel to drive its own saws.
This is the extremist view, and in this area Ayer was something of an extremist. He believed that philosophy's task is to find out what we mean when we say certain things; it is a quest for linguistic clarity. If the results allow the rest of us, non-philosophers, to speak and think more clearly, fine - but that was not the philosopher's aim in the first place. And indeed, in many instances the results may be not at all to our liking. One of the words Ayer used most frequently was "nonsense ". For him, practically all of metaphysics, and absolutely all of religion, is nonsense - not worthless, that is, but rationally without meaning, the happy dreams of self-deluded people; strictly, non-sense.
Simon Blackburn, professor of philosophy at the University of North Carolina, one-time editor of Mind and author of the very useful Oxford Dictionary of Philosophy, is no self-delusionist, but he is firmly convinced that philosophy - or perhaps it would be better to say, the study of philosophy - has practical, everyday uses for all of us. As he says in the first line of Think, the book "grew from years of wrestling with the problems of trying to interest people in ideas".
As he admits, the very word, philosophy, carries unfortunate connotations: "impractical, unwordly, weird", and indeed, it is all of these and more, which is part of its charm. Yet it is practical, wordly, and ordinary, too. Blackburn is refreshingly conservative in his approach to his subject. In his introduction, he promises that "this book stands unashamedly with the tradition and against any modern, or postmodern, scepticism about the value of reflection."
Our ideas and concepts can be compared with the lenses through which we see the world. In philosophy, the lens is itself the topic of study. Success will be a matter not of how much you know at the end, but of what you can do when the going gets tough: when the seas of argument rise, and confusion breaks out. Success will mean taking seriously the implications of ideas.
The book is divided into eight main sections, beginning with Knowledge, and moving on through Mind, Free Will, The Self, God, Reasoning, The World, and ending with a kind of practical how-to chapter, called "What to Do", though it is not as prescriptive as the title might make it sound. One cannot help but like the author - or at least the version of himself that he presents to us through the pages of his book - and this is a help. He must be a very good teacher indeed. His tone is a nice blend of friendliness, clarity, and seriousness without solemnity (the title is an invitation rather than a command). His references range from Plato to Woody Allen, and the section headings themselves are a delight - "Souls and Elastic Balls", "Elephants and Tortoises".
Yet he is careful not to attempt to cosy up to the reader. While he never speaks down, neither does he descend into false humility by pretending that he does not know more about his subject than we do. His irreverence is one of his happiest traits. I liked in particular the character "Dreamboat" - the impossible ideal lover everyone longs for - whom he enlists in a number of examples and propositions, for instance in his demolition of Anselm's ontological proof for the existence of God (and before you take up your pen to write to the Editor, reflect that the ontological argument was rejected by Aquinas himself).
A couple of minor quibbles. The book is a handsome object, and a pleasure to hold in the hand, with clear print on well-proportioned pages (though the paper is unnecessarily stark in its whiteness); the proof-reading, however, is sloppy, which is a shock in the case of a house as grand, or once-grand, as Oxford University Press. And some editor should have caught the reference (twice!) to Copernicus as a Dutchman. It would be churlish to end on a note of complaint. This is a wonderfully stimulating, incisive and - the word is not too strong - thrilling introduction to the pleasures and problems of philosophy. Prof Blackburn believes that "the process of understanding the problems is itself a goal", and that . . .
If the upshot is what Hume called a "mitigated scepticism" or sense of how much a decent modesty becomes us in our intellectual speculations, that is surely no bad thing. The world is full of ideas, and a becoming sense of their power, their difficulty, their frailties, and their fallibility cannot be the least of the things it needs.
John Banville is a novelist and Chief Literary Critic and Associate Literary Editor of The Irish Times