Only human beings have consciousness

Only human beings have consciousness

Herbert Spencer. Principles of biology.

http://www.archive.org/stream/principlesbiolo03spengoog#page/n108/mode/2up

p.96. There is , indeed, another mode of grouping the facts of Biology, with which al are familiar. According as they are facts of animal or vegetal life, they may be classed under the heads of Zoology and Botany. But this division, though convenient and indeed necessary for practical purposes, is one that does not here concern us. Dealing with organic structure and functions in connexion with their causes, conditions, concomitants, and consequences, Biology cannot divide itself into Animal-Biology and Vegetal-Biology; since the same fundamental classes of phenomena are common to both.

p.100. Light is thrown on functions, as well as on structures, by comparing organisms of differents kinds. Comparative Physiology and Comparative Psychology, are the names given to those collections of facts respecting the homologies and analogies, bodily and mental, that are brought to light by this kind of inquiry. These classified observations concerning likenesses and differences of functions, are helpers to interpret functions in their essential natures and relations. Hence Comparative Physiology and Comparative Psychology are names of methods, rather than names of true subdivisions of Biology.