Laura asked:

Does all knowledge come from experience?

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On the surface of things, there are many convincing reasons for thinking that all knowledge comes
from experience. The classic empiricist account of knowledge begins with the question of how
knowledge is acquired. The conclusion, roughly, is that the way we acquire concepts and our
understanding of the world is only through our perceptions of the world. It is from perceptions that all
knowledge comes.

Why be an empiricist? Locke sets about the problem by arguing first of all that none of our ideas are
innate, e.g. our idea of the law of identity, A=A. According to Locke, the 'innatist' may appeal only to
the universal assent of others in support of the view that this idea is innate. Since no principle
receives universal assent, there are no innate ideas. Children and idiots likewise have no idea of such
principles nor would they understand them in all likelihood. So he proposes that the only alternative to
innatism is that we acquire knowledge through experience.

If knowledge is acquired through perception then there must be a real or causal relationship between
the perceptions of the object and the object itself. It is not a straightforward question as to whether it
makes sense to claim that from experience alonewe know that the outside world causes our
perceptions. What would be the basis for claiming that we know that A causes B? A position known
as Direct Realism holds that things as we see them are exactly as they are in themselves; this
position is untenable for a number of reasons, notably because what we see is mediated by our
sense organs. The nature of sound in itself is not the same as the sound that we hear. Sound is a
wave of a certain sort. It sounds different to creatures with different auditory systems. What is the
right way to hear something? The same goes for vision, sensations of smell and taste.

Indirect Realists hold that we see the world via ideas and that our ideas resembleobjects in the world
in greater or lesser degrees. This position brings up a further skeptical problem: on the basis of
experience alone (from which we learn to conceptualise on this view) how do we know that our
sensory experiences — our visual ideas, say — correspond to anything like the way the world is? The
fact that we are able to survive in the world does not entail that we see the world 'as it is'.

As attractive as empiricism may initially seem, the thought that knowledge can only come from
experience leaves the possibility of empirical knowledge virtually out of the question. We know our
ideas because we are immediately acquainted with them but do not know how and in what sense
they correspond to the world. How could ideas even give a good reasonto suppose that there is a
world outside us which they represent? Claims to knowledge involve proposing that one thing is right
in the light of another. Experience on its own — as Wilfred Sellars held — could never be such a
tribunal.

Adam Gatward