nt towards an idealistic philosophy.

"Berkeley faced the problem boldly. He said to the materialists:
'You tell me that all the phenomena of nature are resolvable into
matter and its affections. I assent to your statement, and now I
put to you the further question, What is matter? In answering
this question you shall be bound by your own conditions; and I
demand, in the terms of the Cartesian axiom, that you in turn
give your assent only to such conclusions as are perfectly clear
and obvious.'"

Huxley then goes on to state the general lines of the arguments by
which Berkeley arrived at the apparently paradoxical conclusion "that
all the choir of heaven and furniture of the earth--in a word, all
those bodies which compose the mighty frame of the world," have an
existence only so far as they are in a perceiving mind. And he
proceeds at length to explain the immense importance of the truths
underlying Berkeley's position.

"The key to all philosophy lies in the clear apprehension of
Berkeley's problem--which is neither more nor less than one of
the shapes of the greatest of all questions, 'What are the limits
of our faculties?' And it is worth any amount of trouble to
comprehend the exact nature of the argument by which Berkeley
arrived at his results, and to know by one's own knowledge the
great truth which he discovered--that the honest and rigorous
following up of the argument which leads us to materialism
inevitably carries us beyond it."

Huxley, however, while he opposed a materialistic explanation of the
universe with the strength of exposition and acute reasoning at his
disposal, did not pass directly into the other camp and become a pure
idealist.

"Granting the premisses," he wrote, "I do not see any escape from
Berkeley's conclusion, that the substance of matter is a
metaphysical unknown quantity, of the existence of which there is
no proof. What Berkeley does not seem to have so clearly
perceived is that the non-existence of a substance of mind is
equally arguable; and that the result of the impartial
application of his reasonings is the reduction of the all to
co-existences and sequences of phenomena, beneath and beyond
which there is nothing cognoscible."

Hume had written: "What we call a mind is nothing but a heap or
collection of different perceptions, united together