Darwin’s Eye Problem: Podcast 70This week we look at some problematic conclusions Darwin reaches when looking at his theory. Can his unguided process start the journey up Mount Improbable, or do we need the guiding hand of intelligence?“The abrupt manner in which whole groups of species suddenly appear in certain formations, has been urged by several paleontologists…as a fatal objection to the belief in the transmutation of the species.  If numerous species, belonging to the same genera or families, have really started into life at once, the fact would be fatal to the theory of evolution through natural selection.  For the development by this means of a group of forms, all of which are descended from some one progenitor, must have been an extremely slow process, and the progenitors must have lived long before their modified descendants.  But we continually overrate the perfection of the geological record, and falsely infer, because of certain genera or families have not been found beneath a certain stage, that they did not exist before that stage.  In all cases, positive paleontological evidence may be implicitly trusted; negative evidence is worthless, as experience has so often shown.  Charles Darwin,The Origin of Species,1859  “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.  But I can find out no such case.”  Charles Darwin,The Origin of Species,1859“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.  Reason tells me, that if numerous graduations 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 inseparable 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.”  Charles Darwin,The Origin of Species,1859“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.”  Charles Darwin,The Origin of Species,1859“…the difficulty ceases to be very great in believing that natural selection may have converted the simple apparatus of an optic nerve, coated with a pigment and invested by transparent membrane, into an optical instrument as perfect as possessed by a member of the Articulate Class.”  Charles Darwin,The Origin of Species,1859“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.”  Charles Darwin,The Origin of Species,1859

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