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

to know
anything about the world. This is the topic of Chapter 7.
    However, one piece of optimism is available to us, two centuries
later. We might thus suppose that evolution, which is presumably
responsible for the fact that we have our senses and our reasoning
capacities, would not have selected for them (in the shape in which
we have them) had they not worked. If our eyesight, for example,
did not inform us of predators, food, or mates just when predators,
food, and mates are about, it would be of no use to us. So it is built
to get these things right. The harmony between our minds and the
world is due to the fact that the world is responsible for our minds.
Their function is to represent it so that we can meet our needs; if
they were built to represent it in any way other than the true way,
we could not survive. This is not an argument designed to do away
with the Evil Demon. It is an argument that appeals to things we
take ourselves to know about the world. Unfortunately, we have to
visit in time the area of Hume's doubts, where things we take ourselves to know about the world also serve to make that knowledge seem doubtful.

    A rather different response shrugs off the need for any kind of
'foundations', whether certified by reason, as Descartes hoped, or
merely natural, as in Hume. This approach goes hack to emphasizing instead the coherent structure of our everyday system of beliefs:
the way they hang together, whereas the sporadic experiences or
beliefs we get in dreams are fragmentary and incoherent. It then
points out an interesting feature of coherent structures, namely
that they do not need foundations. A ship or a web may he made up
of a tissue of interconnecting parts, and it derives its strength from
just those interconnections. It does not need a 'base' or a 'starting
point' or 'foundation'. A structure of this kind can have each bit
supported by other bits without there being any bit that supports
all the others without support itself. Similarly, if any one belief is
challenged, others can support it, unless, of course, it turns out that
nothing else supports it, in which case it should be dropped. The
Austrian philosopher Otto Neurath (1882-1945) used this lovely
metaphor for our body of knowledge:
    We are like sailors who on the open sea must reconstruct their
ship but are never able to start afresh from the bottom.
    Any part can he replaced, provided there is enough of the rest on
which to stand. But the whole structure cannot be challenged en
bloc, and if we try to do so, we find ourselves on l)escartes's lonely
rock.
    This approach is usually called 'cohere ntism'. Its motto is that
while every argument needs premises, there is nothing that is the premise of every argument. There is no foundation on which everything rests. Coherentism is nice in one way, but dissatisfying in
another. It is nice in what it does away with, namely the elusive
foundations. It is, however, not clear that it offers us enough to replace them. This is because we seemed able to understand the possibility represented by the Evil Demon-that our system of belief
should be extensive and coherent and interlocking, but all completely wrong. As I said in the introduction to this chapter, even as
children we fall naturally into wondering whether all experience
might be a dream. We might sympathize with Descartes's thought
that if the options are coherentism or scepticism, the more honest
option would be scepticism.

    It is good, then, to remember four options in epistemology
(the theory of knowledge). There is rational foundationalism, as
attempted by Descartes. There is natural foundationalism, as attempted in Hume. There is coherentism. And brooding over all of
them, there is scepticism, or the view that there is no knowledge.
Each of these has had distinguished defenders. Whichever the
reader prefers, he or she will find good philosophical company.
One might think that Descartes got