Although quite an extensive literature has grown up around Spinoza, comparatively little attention has, hitherto, been devoted to his theory of knowledge. The authors of this book have gone into the subject with characteristic German thoroughness, and the results of their investigation are both novel and suggestive. It is one of the most current conceptions, say they, that Spinoza deals in a priori constructions, and deduces his philosophy from definitions which are not taken from experience. They profess to show that, on the contrary, he is the philosopher of experience (Auschauungsphilosoph) par excellence, and that the current conception is due entirely to his method of presentation (p. ix).
Not less striking than their interpretation is their claim that Spinoza is the philosopher of all time κατ' ἐξοχήν, and that his system furnishes the key to the true understanding of the world. The philosophy which they apply to the problems of our time seems to be that of Schopenhauer, rather than that of Spinoza as usually understood. They maintain, however, that the former reproduced the real thoughts of Spinoza, and confess that it has been mainly through a study of his system that they have reached their present position (pp. xi, 270). In the first two hundred pages of the book, the authors explain in a popular way Spinoza's theory of knowledge, and show its wonderful correspondence with the results of modern natural science. The remaining portion is more technical and polemical, and takes account of the existing literature of the subject. The lack of a table of contents is a serious inconvenience in using the book. The proof reading, too, has been very careless, nearly every page being disfigured by typographical errors.
In a scholium to ii, 40 of the Ethics, Spinoza distinguishes three ways in which our knowledge arises. The first kind of knowledge comes through imagination or opinion, and is either the result of unordered experience (vaga experientia), or of attaching certain meanings to words or symbols which we have heard. Knowledge of the second kind Spinoza names reason, and the third intuition. He has explained very clearly what he means by knowledge of the first kind. "When the mind regards external bodies through the ideas of the modifications of its own bodies we say that it imagines" (ii, xvii, note). This must also be extended to the knowledge the mind has of itself, for we find that when we perceive things "after the common order of nature," the mind has no adequate knowledge of itself, of its own body, or of external
