ver
uncertainty there may be in the appearances of nature, arises only out
of the imperfection or variation of the human senses, or possibly from
the deficiency of certain branches of knowledge; when science is able to
apply her tests, the uncertainty is at an end. We are apt sometimes
to think that moral and metaphysical philosophy are lowered by the
influence which is exercised over them by physical science. But any
interpretation of nature by physical science is far in advance of such
idealism. The philosophy of Berkeley, while giving unbounded license to
the imagination, is still grovelling on the level of sense.

We may, if we please, carry this scepticism a step further, and
deny, not only objects of sense, but the continuity of our sensations
themselves. We may say with Protagoras and Hume that what is appears,
and that what appears appears only to individuals, and to the same
individual only at one instant. But then, as Plato asks,--and we must
repeat the question,--What becomes of the mind? Experience tells us by a
thousand proofs that our sensations of colour, taste, and the like,
are the same as they were an instant ago--that the act which we are
performing one minute is continued by us in the next--and also
supplies abundant proof that the perceptions of other men are, speaking
generally, the same or nearly the same with our own. After having slowly
and laboriously in the course of ages gained a conception of a whole and
parts, of the constitution of the mind, of the relation of man to God
and nature, imperfect indeed, but the best we can, we are asked to
return again to the 'beggarly elements' of ancient scepticism, and
acknowledge only atoms and sensations devoid of life or unity. Why
should we not go a step further still and doubt the existence of the
senses of all things? We are but 'such stuff as dreams are made of;'
for we have left ourselves no instruments of thought by which we can
distinguish man from the animals, or conceive of the existence even of a
mollusc. And observe, this extreme scepticism has been allowed to spring
up among us, not, like the ancient scepticism, in an age when nature and
language really seemed to be full of illusions, but in the eighteenth
and nineteenth centuries, when men walk in the daylight of inductive
science.

The attractiveness of such speculations arises out of their true nature
not being perceived. They are veiled in graceful language; they are not
pushed to extr