Think: A Compelling Introduction to Philosophy by Simon Blackburn Read Free Book Online Page B

almost everything right, or
that he got almost everything wrong. The baffling thing is to defend whichever answer commends itself.
    LOCAL SCEPTICISMS
    Scepticism can he raised in particular areas, as well as in the global
fashion of Descartes. Someone might be convinced that we have, say, scientific knowledge, but be very doubtful about knowledge in
ethics or politics or literary criticism. We find particular areas
shortly where it does not take hyperbolic doubt, only a bit of caution, for us to become insecure. However, there are other nice examples of highly general areas where scepticism is baffling. The
philosopher Bertrand Russell (1872-1970) considered the example
of time. How do I know that the world did not come into existence
a very few moments ago, but complete with delusive traces of a
much greater age? Those traces would include, of course, the modifications of the brain that give us what we take to be memories.
They would also include all the other things that we interpret as
signs of great age. In fact, Victorian thinkers struggling to reconcile
the biblical account of the history of the world with the fossil
record had already suggested much the same thing about geology.
On this account, around 4,000 years ago God laid down all the misleading evidence that the earth is about 4,000 million years old
(and, we can now add, misleading signs that the universe is about
13,000 million years old). This was never a popular move, probably
because if you are sceptical about time, you quickly become sceptical about everything, or maybe because it presents God as something like a large-scale practical joker. Russell's possibility sounds
almost as far-fetched as Descartes's Evil Demon.

    However, there is one highly intriguing thing about Russell's
scenario. This is that it can actually be argued to be scientifically
more probable than the alternative we all believe in! This is because
science tells us that `low-entropy' or, in other words, highly ordered
systems are more improbable. In addition, as physical systems like
the cosmos evolve, entropy or disorder increases. The smoke never returns into the cigarette; the toothpaste never goes back into the
tube. The extraordinary thing is that there was ever enough order in
things for the smoke to be in the cigarette or the toothpaste to be in
the tube in the first place. So, one might argue, it is `easier' for a
moderately disordered world, such as the world is now, to come
into existence, than it is for any lower-entropy, more orderly ancestor. Intuitively, it is as if there are more ways this can happen, just as
there are more ways you can get four-letter or five-letter words in
an initial hand of seven letters in Scrabble, than there are in which
you can get a seven-letter word. It is much more probable that you
get a four-letter word than a seven-letter word. Similarly, the argument goes, it is as if God or Nature had less to do, to make the world
as it is today out of nothing, than to make the lower-entropy world
as it is supposed to have been some thirteen billion years ago out of
nothing. Therefore, it is more probable that it happened like that.
In a straight competition for probability between Russell's outlandish hypothesis and common sense, Russell wins. I leave this for
the reader to ponder.

    THE MORAL
    How then should we regard knowledge? Knowledge implies authority. the people who know are the people to whom we should
listen. It implies reliability: the people who know are those who are
reliable at registering the truth, like good instruments. To claim
knowledge implies claiming a sense of our own reliability. And to
accord authority to someone or some method involves seeing it as reliable. The unsettling scenarios of a Descartes or a Russell unseat
our sense of our own reliability. Once we have raised the outlandish possibilities, our sense of a reliable connection between the
way things are and the ways we take them to