"We only know physical objects and only objects relative to these beings (_êtres_): such is the condition of our nature. If our thoughts, our reasonings, our principles have been considered as metaphysical objects, these objects, then, are not beings (_êtres_). They are only relations or consequences of relations (_rapports_), or only results of observed laws. "We know that relations are distinguished as general and special. Among these last are regarded those of nature, form, dimension, solidity, size, quantity, resemblance, and difference; and if we add to these objects the being observed and the consideration of known laws, as also that of conventional objects, we shall have all the materials on which our thoughts are based. "Thus being able to observe only the phenomena of nature, as well as the laws which regulate these phenomena, also the products of these last, in a word, only bodies (_corps_) and what concerns them, all that which immediately proceeds from supreme power is incomprehensible to us, as it itself [_i.e._, supreme power] is to our minds. To create, or to make anything out of nothing, this is an idea we cannot conceive of, for the reason that in all that we can know, we do not find any model which represents it. GOD alone, then, can create, while nature can only produce. We must suppose that, in his creations, the Divinity is not restricted to the use of any time, while, on the other hand, nature can effect nothing without the aid of long periods of time." Without translating more of this remarkable book, which is very rare, much less known than the _Philosophie zoologique_, the spirit of the remainder may be imagined from the foregoing extracts. The author refers to the numerous evils resulting from ignorance, false knowledge, lack of judgment, abuse of power, demonstrating the necessity of our confining ourselves within the circle of the objects presented by nature, and never to go beyond them if we do not wish to fall into error, because the profound study of nature and of the organization of man alone, and the exact observation of facts alone, will reveal to us "the truths most important for us to know," in order to avoid the vexations, the perfidies, the injustices, and the oppressions of all sorts, and "incalculable disorders" which arise in the social body. In this way only shall we discover and acquire the means of obtaining the enjoyment of the advantages which we have a right to expect from our state of civilization. The author endeavors to state what science can and should render to society. He dwells on the sources from which man has drawn the knowledge which he possesses, and from which he can obtain many others--sources the totality of which constitutes for him the field of realities. Lamarck also in this work has built up a system for moral philosophy. Self-love, he says, perfectly regulated, gives rise: