h, especially in infancy. The confirmation of them by one another
cannot of course be given by any one of them. Many intuitions which are
inseparable from the act of sense are really the result of complicated
reasonings. The most cursory glance at objects enables the experienced
eye to judge approximately of their relations and distance, although
nothing is impressed upon the retina except colour, including gradations
of light and shade. From these delicate and almost imperceptible
differences we seem chiefly to derive our ideas of distance and
position. By comparison of what is near with what is distant we learn
that the tree, house, river, etc. which are a long way off are objects
of a like nature with those which are seen by us in our immediate
neighbourhood, although the actual impression made on the eye is very
different in one case and in the other. This is a language of 'large and
small letters' (Republic), slightly differing in form and exquisitely
graduated by distance, which we are learning all our life long, and
which we attain in various degrees according to our powers of sight or
observation. There is nor the consideration. The greater or less strain
upon the nerves of the eye or ear is communicated to the mind and
silently informs the judgment. We have also the use not of one eye only,
but of two, which give us a wider range, and help us to discern, by the
greater or less acuteness of the angle which the rays of sight form,
the distance of an object and its relation to other objects. But we are
already passing beyond the limits of our actual knowledge on a subject
which has given rise to many conjectures. More important than the
addition of another conjecture is the observation, whether in the case
of sight or of any other sense, of the great complexity of the causes
and the great simplicity of the effect.

The sympathy of the mind and the ear is no less striking than
the sympathy of the mind and the eye. Do we not seem to perceive
instinctively and as an act of sense the differences of articulate
speech and of musical notes? Yet how small a part of speech or of music
is produced by the impression of the ear compared with that which is
furnished by the mind!

Again: the more refined faculty of sense, as in animals so also in man,
seems often to be transmitted by inheritance. Neither must we forget
that in the use of the senses, as in his whole nature, man is a social
being, who is always being educated by