The case of shamming sickness, quoted from K. Russ, is thus interpreted by Professor Groos.[171] And yet he adds, “When we see deception used so effectively to serve practical ends, examples of which are very common, it can hardly be doubted that there is in all probability more consciousness of shamming in play than we have any means of demonstrating.” And elsewhere in the same work he observes,[172] “Many a grown animal still takes pleasure in the mock combats that he learned in youth. From a psychological point of view this phenomenon is especially noteworthy, from the fact that the adult animal, though already well acquainted with real fighting, still knows how to keep within the bounds of play, and must therefore be consciously playing a _rôle_, making believe.” I fail, however, to see the justification for the “therefore.” Surely the difference of behaviour in this example, and in other such examples, is sufficiently explained as the outcome of diverse situations, without having recourse to anything so psychologically complex as the conscious self-illusion of make-believe--interesting and important as this is in the psychology of children. To suppose that a monkey who nurses a bit of blanket has any ideas about its being a make-believe baby is _not_ to interpret the behaviour of animals in accordance with the canon we have adopted for our guidance. To return to the “ethics” of animals. I have urged that ethical ideas, properly so called, have no place in their psychology. But just as the pleasure and satisfaction attending particular situations, as they severally arise, appear to contain the perceptual germs of what in later development becomes æsthetic appreciation; so, too, do they also contain the perceptual germs of what becomes, through reflection in man, ethical approbation. And the situations in which these ethical germs must be sought are those which entail behaviour for the good of the social community. Indeed, we may go so far as to say that the perceptual foundations of ethics are laid in the social instincts. The satisfaction or dissatisfaction arising from the performance or non-performance of instinctive behaviour, evolved for the biological end of the preservation of the social community, is the perceptual embryo from which conscience is developed. Professor Mackenzie has indicated the ambiguities in the use of the term “conscience.” “It is,” he says,[173] “sometimes used to express the fundamental principles on which the moral judgment rests; at other times it expresses the principles adopted by a particular individual; at other times it means ‘a particular kind of pleasure or pain felt in perceiving our own conformity or nonconformity to principle.’[174] This last seems to me,” adds Mr. Mackenzie, “the most convenient acceptation of the term, except that I should prefer to say simply that it is a feeling of pain accompanying and resulting from our nonconformity to principle.”