It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is the most adaptable to change.
Nothing exists for itself alone, but only in relation to other forms of life
Animals, whom we have made our slaves, we do not like to consider our equal.
As for a future life, every man must judge for himself between conflicting vague probabilities.
Physiological experiment on animals is justifiable for real investigation, but not for mere damnable and detestable curiosity.
A scientific man ought to have no wishes, no affections, - a mere heart of stone.
On the ordinary view of each species having been independently created, we gain no scientific explanation.
There is no fundamental difference between man and the higher animals in their mental faculties... The lower animals, like man, manifestly feel pleasure and pain, happiness, and misery.
False facts are highly injurious to the progress of science, for they often endure long; but false views, if supported by some evidence, do little harm, for every one takes a salutary pleasure in proving their falseness.
To kill an error is as good a service as, and sometimes even better than, the establishing of a new truth or fact.
The mystery of the beginning of all things is insoluble by us; and I for one must be content to remain an agnostic
The love for all living creatures is the most noble attribute of man.
False facts are highly injurious to the progress of science, for they often endure long; but false views, if supported by some evidence, do little harm, for everyone takes a salutory pleasure in proving their falseness; and when this is done, one path toward errors is closed and the road to truth is often at the same time opened.
It is a cursed evil to any man to become as absorbed in any subject as I am in mine
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.