Materialistic accounts of human nature are often thought to fail just because human beings seem to have properties, such as thought and freedom, that matter does not have. In making matter a genus of varied beings, Holbach creates a view flexible enough to accommodate an account of human nature more robust than that of many other materialists:
…Man is, as a whole, the result of a certain combination of matter, endowed with particular properties, competent to give, capable of receiving, certain impulses, the arrangement of which is called organization, of which the essence is, to feel, to think, to act, to move, after a manner distinguished from other beings with which he can be compared. Man, therefore, ranks in an order, in a system, in a class by himself, which differs from that of other animals, in whom we do not perceive those properties of which he is possessed. [ System of Nature 15]
Holbach's naturalism requires that human nature be understood in terms of laws and that human action be comprehended under universal determinism. But it allows that, in many ways, human beings may differ in kind from other bodies, even animals, and it allows that human beings may have many properties, notably thought, that have traditionally been denied to …show more content…
Matter can to some extent be understood the ordinary sense of anything that has extention, figure, and so on. However, because matter also may or may not have any number of properties not ordinarily understood to belong to matter, such as thought, it is not entirely clear what may not be matter. Motion is likewise and for similar reasons a vague term in Holbach. Where matter is understood simply as extension and some other very simple properties, motion may be thought of in similarly simple terms, as a velocity, acceleration or, perhaps, as an impulse with a certain direction. Once matter is thought of, after the manner of Holbach, as something with properties which are perhaps best not understood in spatial terms, its motion may be much more difficult to define. Although he sometimes speaks of matter and motion in narrower senses, Holbach's tendency is simply to identify matter and motion with the general terms cause and effect. Holbach typically identifies bodies with causes and motions with effects, but he also allows that motions may be