Man is an animal with primary instincts of survival. Consequently, his ingenuity has developed first and his soul afterwards. The progress of science is far ahead of man's ethical behavior.

Nevertheless it is probable that the hearing rather early in life such views maintained and praised may have favoured my upholding them under a different form in my 'Origin of Species.

A fair result can be obtained only by fully stating and balancing the facts and arguments on both sides of each question.

I have steadily endeavoured to keep my mind free so as to give up any hypothesis, however much beloved (and I cannot resist forming one on every subject), as soon as facts are shown to be opposed to it.

Ignorance more frequently begets confidence than does knowledge: it is those who know little, and not those who know much, who so positively assert that this or that problem will never be solved by science.

It is no valid objection that science as yet throws no light on the far higher problem of the essence or origin of life. Who can explain the what is the essence of the attraction of gravity?