Perception, in normal circumstances, is accepted by all as a matter of course or, rather, of necessity: it controls the activities of practical life in hunting and in industry, in making weapons, hoeing the ground, building houses: however, these labours may sometimes be modified or interrupted by the intrusion of beliefs derived from other sources. If a savage sings a spell to his prey, or weapon, or tool, or keeps the head of a slain enemy on a shelf that his victim’s soul may assist him as a slave, he may thereby increase his own confidence in the work of hunting or gardening; but, otherwise, if his work be no better, neither need it be the worse for such fancies. The properties of matter exact practical recognition, without which nothing can be done. Even magical practices presuppose a sane perception of the central facts: as who is acting, for what purpose, when and where, with what and toward whom. Upon this basis there may be an astonishing superstructure of imagination-belief; but there are limits to the effectiveness of such beliefs. M. Levy-Bruhl, indeed, in a very interesting book, maintains[88] that, under the influence of social ideas (_représentations collectives_), the primitive mind actually perceives things differently from what we do. Whilst we succeed in attaining an objective presentation, eliminating subjective associations, with primitives _propriétés mystique_, _forces occultes_ are integral qualities of the object. He grants that, in certain cases of immediate practical interest, we find them very attentive and able to discriminate slight impressions, and to recognise the external signs of an object on which their subsistence or even their life depends; but holds that, in a very great majority of cases, their perceptions are over-weighted by subjective elements. This doctrine reverses (I venture to think) the real relations between perceptions and other causes of belief and their proportionate influence in savage life. It is not only where subsistence or life is at stake that backward peoples see things as they are: in merely experimental tests, Dr. Rivers found amongst both Papuans and Todas, that, as to suggestibility in perception, they showed a high degree of independence of judgment.[89] Their confidence in perception is not, like imagination-belief, occasional, modifiable for convenience, liable to lapse in course of time, dependent on the assent of a crowd. So far as occult or mystical attributes are by a savage assigned to things, such as magical force to a weapon, they constitute a secondary, imaginary integration with the percept. Such imaginary attributes cannot, like perception attributes, be verified by sensation: compare the hardness of a spearhead with its magical force.