Manifestly, we could not live otherwise, and the spread of scientific knowledge is the further tracing out of such "laws"-that is to say, the ways of behaving of existence-and the extending of our belief in their invariability to wider and wider fields.
"The Book of Life: Vol. I Mind and Body; Vol. II Love and Society"
Upton Sinclair
Thus John Stuart Mill says:- "The Law of Causation, the recognition of which is the main pillar of inductive science, is but the familiar truth, that invariability of succession is found by observation to obtain between every fact in nature and some other fact which has preceded it."
"Mysticism and Logic and Other Essays"
Bertrand Russell
Even metamorphoses, he adds, "have all the constancy and invariability of other modes of embryonic growth, and have never been known to lead to any transition of one species into another."
"Louis Agassiz: His Life and Correspondence"
Louis Agassiz