ABSTRACT
The fundamental theory of comparative psychology is the Darwinian theory of evolution by natural selection. Shortly after Darwin published The Origin of Species in 1859 (see Darwin, 1985), his “bulldog,” Thomas Huxley, anticipated this conclusion in a frequently reprinted lecture to workingmen delivered in 1860:
I have endeavoured to show that no absolute structural line of demarcation, wider than that between the animals which immediately succeed us in the scale, can be drawn between the animal world and ourselves; and I my add the expression of my belief that the attempt to draw a psychical distinction is equally futile, and that even the highest faculties of feeling and intellect begin to germinate in lower forms of life. (1899, p. 152)
