That sad creationist, Professor Dendy, has been banned from this site, but he still rails against us in prolific obsession from his website. His latest diatribe is irresistible — he claims that atheists can’t handle the truth, and you’ll be surprised to learn that the “truth” is that Charles Darwin denied the efficacy of natural selection. “Oh, really,” you might ask, “He’s not going to trot out the hoariest old quote mine in the universe to back that up, is he?” And the answer is that yes, he certainly is. I had to laugh aloud. This is only second in the list of ridiculous but common claims made by creationists (first, of course, being “if evolution is true, why are there still monkeys?”).
He thinks he’s got us up against the wall with the terrifying truth of the complexity of the eye.
The truth of the matter is that even Charles Darwin himself said it would be absurd to think that the complex eye could been formed by natural selection.
Then he lists a few eyeball facts just to make us squirm. I’m sorry, Professor Dendy, but someone else has done this with far more detail and style than you ever had. I give you the inestimable William Paley, who made the same argument 208 years ago.
Were there no example in the world, of contrivance, except that of the eye, it would be alone sufficient to support the conclusion which we draw from it, as to the necessity of an intelligent Creator. It could never be got rid of; because it could not be accounted for by any other supposition, which did not contradict all the principles we possess of knowledge; the principles, according to which, things do, as often as they can be brought to the test of experience, turn out to be true or false. Its coats and humours, constructed, as the lenses of a telescope are constructed, for the refraction of rays of light to a point, which forms the proper action of the organ; the provision in its muscular tendons for turning its pupil to the object, similar to that which is given to the telescope by screws, and upon which power of direction in the eye, the exercise of its office as an optical instrument depends; the further provision for its defence, for its constant lubricity and moisture, which we see in its socket and its lids, in its gland for the secretion of the matter of tears, its outlet or communication with the nose for carrying off the liquid after the eye is washed with it; these provisions compose altogether an apparatus, a system of parts, a preparation of means, so manifest in their design, so exquisite in their contrivance, so successful in their issue, so precious, and so infinitely beneficial in their use, as, in my opinion, to bear down all doubt that can be raised upon the subject.
William Paley, Natural Theology; or, Evidences of the Existence and Attributes of the Deity, 1802
Oh, gosh…Paley and Dendy, double-teaming us with two-century-old opinions. However shall we cope?
This really is an old and moldy argument. Charles Darwin dealt with it effectively 150 years ago, and I strongly urge Dendy to read beyond the first sentence he quoted, since from the second sentence on he shows that the supposition is false.
Just to be sure no one misses it, I’ve included the entirety of the section from Chapter VI, “Difficulties of the Theory: Organs of extreme Perfection and Complication” below the fold. The point of his argument is not, “Oh, no, selection fails!” but “Oh, look — selection can explain even these organs that seem absurdly complex.”
To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree. When it was first said that the sun stood still and the world turned round, the common sense of mankind declared the doctrine false; but the old saying of Vox populi, vox Dei, as every philosopher knows, cannot be trusted in science. Reason tells me, that if numerous gradations from a simple and imperfect eye to one complex and perfect can be shown to exist, each grade being useful to its possessor, as is certainly the case; if further, the eye ever varies and the variations be inherited, as is likewise certainly the case and if such variations should be useful to any animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, should not be considered as subversive of the theory. How a nerve comes to be sensitive to light, hardly concerns us more than how life itself originated; but I may remark that, as some of the lowest organisms, in which nerves cannot be detected, are capable of perceiving light, it does not seem impossible that certain sensitive elements in their sarcode should become aggregated and developed into nerves, endowed with this special sensibility.
In searching for the gradations through which an orgain in any
species has been perfected, we ought to look exclusively to its lineal
progenitors; but this is scarcely ever possible, and we are forced
to look to other species and genera of the same group, that is to
the collateral descendants from the same parent-form, in order to
see what gradations are possible, and for the chance of some
gradations having been transmitted in an unaltered or little altered
condition. But the state of the same organ in distinct classes may
incidentally throw light on the steps by which it has been perfected.
The simplest organ which can be called an eye consists of an optic
nerve, surrounded by pigment-cells, and covered by translucent skin,
but without any lens or other refractive body. We may, however,
according to M. Jourdain, descend even a step lower and find
aggregates of pigment-cells, apparently serving as organs of vision,
without any nerves, and resting merely on sarcodic tissue. Eyes of the
above simple nature are not capable of distinct vision, and serve only
to distinguish light from darkness. In certain star-fishes, small
depressions in the layer of pigment which surrounds the nerve are
filled, as described by the author just quoted, with transparent
gelatinous matter, projecting with a convex surface, like the cornea
in the higher animals. He suggests that this serves not to form an
image, but only to concentrate the luminous rays and render their
perception more easy. In this concentration of the rays we gain the
first and by far the most important step towards the formation of a
true, picture-forming eye; for we have only to place the naked
extremity of the optic nerve, which in some of the lower animals
lies deeply buried in the body, and in some near the surface, at the
right distance from the concentrating apparatus, and an image will
be formed on it.
In the great class of the Articulata, we may start from an optic
nerve simply coated with pigment, the latter sometimes forming a
sort of pupil, but destitute of a lens or other optical contrivance.
With insects it is now known that the numerous facets on the cornea of
their great compound eyes form true lenses, and that the cones include
curiously modified nervous filaments. But these organs in the
Articulata are so much diversified that Muller formerly made three
main classes with seven subdivisions, besides a fourth main class of
aggregated simple eyes.
When we reflect on these facts, here given much too briefly, with
respect to the wide, diversified, and graduated range of structure
in the eyes of the lower animals; and when we bear in mind how small
the number of all living forms must be in comparison with those
which have become extinct, the difficulty ceases to be very great in
believing that natural selection may have converted the simple
apparatus of an optic nerve, coated with pigment and invested by
transparent membrane, into an optical instrument as perfect as is
possessed by any member of the articulate class.
He who will go thus far, ought not to hesitate to go one step
further, if he finds on finishing this volume that large bodies of
facts, otherwise inexplicable, can be explained by the theory of
modification through natural selection; he ought to admit that a
structure even as perfect as an eagle’s eye might thus be formed,
although in this case he does not know the transitional states. It has
been objected that in order to modify the eye and still preserve it as
a perfect instrument, many changes would have to be effected
simultaneously, which, it is assumed, could not be done through
natural selection; but as I have attempted to show in my work on the
variation of domestic animals, it is not necessary to suppose that the
modifications were all simultaneous, if they were extremely slight and
gradual. Different kinds of modification would, also, serve for the
same general purpose: as Mr. Wallace has remarked, “if a lens has
too short or too long a focus, it may be amended either by an
alteration of curvature, or an alteration of density; if the curvature
be irregular, and the rays do not converge to a point, then any
increased regularity of curvature will be an improvement. So the
contraction of the iris and the muscular movements of the eye are
neither of them essential to vision, but only improvements which might
have been added and perfected at any stage of the construction of
the instrument.” Within the highest division of the animal kingdom,
namely, the Vertebrata, we can start from an eye so simple, that it
consists, as in the lancelet, of a little sack of transparent skin,
furnished with a nerve and lined with pigment, but destitute of any
other apparatus. In fishes and reptiles, as Owen has remarked, “the
range of gradations of dioptric structures is very great.” It is a
significant fact that even in man, according to the high authority
of Virchow, the beautiful crystalline lens is formed in the embryo
by an accumulation of epidermic cells, lying in a sack-like fold of
the skin; and the vitreous body is formed from embryonic sub-cutaneous
tissue. To arrive, however, at a just conclusion regarding the
formation of the eye, with all its marvellous yet not absolutely
perfect characters, it is indispensable that the reason should conquer
the imagination; but I have felt the difficulty far too keenly to be
surprised at others hesitating to extend the principle of natural
selection to so startling a length.
It is scarcely possible to avoid comparing the eye with a telescope.
We know that this instrument has been perfected by the
long-continued efforts of the highest human intellects; and we
naturally infer that the eye has been formed by a somewhat analogous
process. 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
spaces filled with fluid, and 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, represented by
natural selection or the survival of the fittest, always intently
watching each slight alteration in the transparent layers; and
carefully preserving each which, under varied circumstances, in any
way or in any degree, tends to produce a distincter image. We must
suppose each new state of the instrument to be multiplied by the
million; each to be preserved until a better one is produced, and then
the old ones to be all 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 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?
Charles Darwin, the Origin, 1859
The Darwin quotemine on the subject of the eye is one of the most notorious markers of creationist dishonesty — to cite that chapter as suggesting that Darwin was proposing that his theory was invalid, when the whole thing is an argument for the exact opposite, is one reason we should treat creationism as beneath contempt. It’s also an indicator that Professor Dendy is incompetent in biology, and it’s shocking that he continues to teach at an American college.