truth which we were taught or which we inherited has never been
contradicted in all our experience and is therefore confirmed by it. Who
can resist an idea which is presented to him in a general form in every
moment of his life and of which he finds no instance to the contrary? The
greater part of what is sometimes regarded as the a priori intuition of
space is really the conception of the various geometrical figures of which
the properties have been revealed by mathematical analysis. And the
certainty of these properties is immeasurably increased to us by our
finding that they hold good not only in every instance, but in all the
consequences which are supposed to flow from them.

Neither must we forget that our idea of space, like our other ideas, has a
history. The Homeric poems contain no word for it; even the later Greek
philosophy has not the Kantian notion of space, but only the definite
'place' or 'the infinite.' To Plato, in the Timaeus, it is known only as
the 'nurse of generation.' When therefore we speak of the necessity of our
ideas of space we must remember that this is a necessity which has grown up
with the growth of the human mind, and has been made by ourselves. We can
free ourselves from the perplexities which are involved in it by ascending
to a time in which they did not as yet exist. And when space or time are
described as 'a priori forms or intuitions added to the matter given in
sensation,' we should consider that such expressions belong really to the
'pre-historic study' of philosophy, i.e. to the eighteenth century, when
men sought to explain the human mind without regard to history or language
or the social nature of man.

In every act of sense there is a latent perception of space, of which we
only become conscious when objects are withdrawn from it. There are
various ways in which we may trace the connexion between them. We may
think of space as unresisting matter, and of matter as divided into