Thomas Henry Huxley

It is an error to imagine that evolution signifies a constant tendency to increased perfection. That process undoubtedly involves a constant remodeling of the organism in adaptation to new conditions; but it depends on the nature of those conditions whether the direction of the modifications effected shall be upward or downward.
‘The Struggle for Existence in Human Society’ (1888). In Collected Essays (1894), Vol. 9, 199.