W. R. Thompson quotes:

This general tendency to eliminate, by means of unverifiable speculations, the limits of the categories nature presents to us is the inheritance of biology from The Origin of Species. To establish the continuity required by theory, historical arguments are invoked, even though historical evidence is lacking. Thus are engendered those fragile towers of hypothesis based on hypothesis, where fact and fiction intermingle in an inextricable confusion.

I am not satisfied that Darwin proved his point or that his influence in scientific and public thinking has been beneficial ... the success of Darwinism was accomplished by a decline in scientific integrity.

The success of Darwinism was accomplished by a decline in scientific integrity.

This situation, where men rally to the defense of a doctrine they are unable to define scientifically, much less demonstrate with scientific rigor, attempting to maintain its credit with the public by the suppression of criticism and the elimination of difficulties, is abnormal and undesirable in science.