But may not
this inference be presumptuous? Have we any right to assume that the
Creator works by intellectual powers like those of man? If we must
compare the eye to an optical instrument, we ought in imagination to
take a thick layer of transparent tissue, with a nerve sensitive to
light beneath, and then suppose every part of this layer to be
continually changing slowly in density, so as to separate into layers
of different densities and thicknesses, placed at different distances
from each other, and with the surfaces of each layer slowly changing
in form. Further we must suppose that there is a power always intently
watching each slight accidental alteration in the transparent layers;
and carefully selecting each alteration which, under varied
circumstances, may in any way, or in any degree, tend to produce a
distincter image. We must suppose each new state of the instrument to
be multiplied by the million; and each to be preserved till a better
be produced, and then the old ones to be destroyed. In living bodies,
variation will cause the slight alterations, generation will multiply
them almost infinitely, and natural selection will pick out with
unerring skill each improvement. Let this process go on for millions
on millions of years; and during each year on millions of individuals
of many kinds; and may we not believe that a living optical instrument
might thus be formed as superior to one of glass, as the works of the
Creator are to those of man?
If it could be demonstrated that any complex organ existed, which
could not possibly have been formed by numerous, successive, slight
modifications, my theory would absolutely break down.
Pages:
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236