- (2) The second position, which is solipsism as ordinarily understood, allows some
inference from my percepts, but only to other events in my own biography. Take, for
example, the view that, at any moment in waking life, there are sensible objects that we
do not notice. We see many things without saying to ourselves that we see them; at least,
so it seems. Keeping the eyes fixed in an environment in which we perceive no
movement, we can notice various things in succession, and we feel persuaded that they
were visible before we noticed them; but before we noticed them they were not data for
theory of knowledge. This degree of inference from what we observe is made
unreflectingly by everybody, even by those who most wish to avoid an undue extension
of our knowledge beyond experience. - (3) The third position--which seems to be held, for instance, by Eddington--is that it is
possible to make inferences to other events analogous to those in our own experience,
and that, therefore, we have a right to believe that there are, for instance, colours seen by
other people but not by ourselves, toothaches felt by other people, Pleasures enjoyed and
pains endured by other people, and so on, but that we have no right to infer events
experienced by no one and not forming part of any "mind." This view may be defended
on the ground that all inference to events which lie outside my observation is by analogy,
and that events which no one experiences are not
-656-sufficiently analogous to my data to warrant analogical inferences.- (4) The fourth position is that of common sense and traditional physics, according to
which there are, in addition to my own experiences and other people's, also events which
no one experiences--for example, the furniture of my bedroom when I am asleep and it is
pitch dark. G. E. Moore once accused idealists of holding that trains only have wheels
while they are in stations, on the ground that passengers cannot see the wheels while they
remain in the train. Common sense refuses to believe that the wheels suddenly spring
into being whenever you look, but do not bother to exist when no one is inspecting them.
When this point of view is scientific, it bases the inference to unperceived events on
causal laws.