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Charles Darwin was Never Completely Happy with His Theory of Evolution

Darwin's Doubts

Charles Darwin advanced a theory.  In 1859 he published his book 'On the Origin of Species' in which he suggested the idea that one species could arise from another, and that the driving force behind this was 'natural selection' so the individual most fitted to survive would survive.

Charles Darwin was a scientist.  He was fully expecting his theory to be tested against scientific evidence by other scientists.  Further than that he continued thinking about the theory.  He was never completely happy with it.  To Darwin, the theory on evolution by natural selection did not explain everything to his satisfaction. In my article 'The Eye' Darwin's explanation of the evolution of the eye is mentioned.

Darwin's doubts were of many kinds.  One of his doubts concerned the mechanism of inheritance.  If, as was usually accepted in those days, the offspring will be a blend of the parents, so, for example, a person with one tall parent and one short one will be of medium height, how could taller people evolve?

In fact, within Darwin's own lifetime part of the answer was found.  Gregor Mendel ( A monk) did some experiments with peas.  He found, for example, that if he crossed a tall pea plant with a short one, the offspring was not part way between the two heights.  In his first cross all the pea plants of the next generation were tall.  Mendel found by further experiments that the 'short' characteristic had not been destroyed by being mixed with the 'tall' one, but was still there in the plant so it could still express itself in later generations.




Charles Darwin

Gregor Mendel