The Problems of Philosophy

by Bertrand Russell

'Whatever can be thought of is an idea in the mind of the person thinking of it; therefore nothing can be thought of except ideas in minds; therefore anything else is inconceivable, and what is inconceivable cannot exist.'

exactly the space we see or feel. To begin with,

whatever we can apprehend must be in our minds.

(a) When a thing of a certain sort A has been found to be associated with a thing of a certain other sort B, and has never been found dissociated from a thing of the sort B, the greater the number of cases in which A and B have been associated, the greater is the probability that they will be associated in a fresh case in which one of them is known

to be present; (b) Under the same circumstances, a sufficient number of cases of association will make the probability of a fresh association nearly a certainty, and will make it approach certainty without limit.

philosophers, who maintained that experience was as much the source of our knowledge of arithmetic as of our knowledge of geography. They maintained