and suggests inquiry into the
nature of those physical conditions, or concomitants of thought, which
are more or less accessible to us, and a knowledge of which may, in
future, help us to exercise the same kind of control over the world of
thought as we already possess in respect of the material world;
whereas, the alternative, or spiritualistic, terminology is utterly
barren, and leads to nothing but obscurity and confusion of ideas.

Thus there can be little doubt, that the further science advances, the
more extensively and consistently will all the phenomena of Nature be
represented by materialistic formulae and symbols.

But the man of science, who, forgetting the limits of philosophical
inquiry, slides from these formulae and symbols into what is commonly
understood by materialism, seems to me to place himself on a level with
the mathematician who should mistake the x's and y's with which he works
his problems, for real entities--and with this further disadvantage, as
compared with the mathematician, that the blunders of the latter are of
no practical consequence, while the errors of systematic materialism may
paralyse the energies and destroy the beauty of a life.

FOOTNOTES:

[Footnote 48: The substance of this paper was contained in an address
which was delivered in Edinburgh in 1868. The paper was published in
"Lay Sermons," 1870.]

[Footnote 49: _a fortiori:_ with stronger reason.]

[Footnote 50: Why does the populace rush so and make clamor? It wishes
to eat, bring forth children, and feed these as well as it may.... No
man can do better, strive how he will.]

[Footnote 51: We and ours must die.]

[Footnote 52: In one of the Arabian Nights stories, a nobleman called
Barmecide set before a beggar a number of empty dishes supposed to
contain a feast.]

[Footnote 53: Mode of working.]

[Footnote 54: Archaeus: a spirit, having essentially the same form as
the body within which it resided.]

[Footnote 55: Hume's Essay "Of the Academical or Sceptical Philosophy,"
in the _Inquiry concerning the Human Understanding._--[Many critics of
this passage seem to forget that the subject-matter of Ethics and
Aesthetics consists of matters of fact and existence.--1892.]--Author's
note.]

[Footnote 56: Or, to speak more accurately, the physical state of which
volition is the expression.--1892.--Author's note.]

COMPARISON OF THE MENTAL POWERS OF MAN AND THE LOWER ANIMALS[57]

CHARLES DARWIN

My objec