executing successfully this chart or tree, a philosophical delineation of the natural progress of the mind may (according to him) furnish very useful lights; although he acknowledges that the results of the two undertakings cannot fail to differ widely in many instances the laws which regulate the generation of our ideas often interfering with that systematical order in the relative arrangement of scientific pursuits, which it is the purpose of the Encyclopedical Tree to exhibit.[1]
In treating of the first of these subjects, it cannot be denied that D'Alembert has displayed much ingenuity and invention; but the depth and solidity of his general train of thought may be questioned. On various occasions, he has evidently suffered himself to be misled by a spirit of false refinement; and on others, where probably he was fully aware of his inability to render the theoretical chain complete, he seems to have aimed at concealing from his readers the faulty links, by availing himself of those epigrammatic points, and other artifices of style, with which the genius of the French language enables a skilful writer to smooth and varnish over his most illogical transitions.
The most essential imperfections, however, of this historical sketch, may be fairly ascribed to a certain vagueness and indecision in the author's idea, with regard to the scope of his inquiries. What he has in general pointed at is to trace, from the theory of the Mind, and from the order followed by nature in the development of its powers, the successive steps by which
- ↑ The true reason of this might perhaps have been assigned in simpler terms, by remarking that the order of invention is, in most cases, the reverse of that fitted for didactic communication. This observation applies not only to the analytical and synthetical processes of the individual, but the the progressive improvements of the species, when compared with the arrangements prescribed by logical method for conveying a knowledge of them to students. In an enlightened age, the sciences are justly considered as the basis of the arts; and, in a course of liberal education, the former are always taught prior to the latter. But, in the order of invention and discovery, the arts preceeded the sciences. Men measured land before they studied speculative geometry; and governments were established before politics were studied as a science. A remark somewhat similar is made by Celsus concerning the history of medicine: "Non medicinam rationi essec posteriorem, sed post medicinam inventam, rationon essc quæsitam."
