Failure is instructive. The person who really thinks learns quite as much from his failures as from his successes. Genuine ignorance is profitable because it is likely to be accompanied by humility, curiosity, and open-mindedness; whereas ability to repeat catch-phrases, cant terms, familiar propositions, gives the conceit of learning and coats the mind with varnish waterproof to new ideas.
The path of least resistance and least trouble is a mental rut already made. It requires troublesome work to undertake the alternation of old beliefs. Self-conceit often regards it as a sign of weakness to admit that a belief to which we have once committed ourselves is wrong. We get so identified with an idea that it is literally a pet notion and we rise to its defense and stop our eyes and ears to anything different.
In laying hands upon the sacred ark of absolute permanency, in treating the forms that had been regarded as types of fixity and perfection as originating and passing away, the Origin of Species introduced a mode of thinking that in the end was bound to transform the logic of knowledge, and hence the treatment of morals, politics, and religion.