First come the separate letters of the alphabet ; then combinations of letters into words and of words into sentences, etc., in accord ance with the laws of grammar; lastly comes the stage when the significance of a whole sentence or paragraph is grasped at a glance. So it is with the great book of Nature. First comes the perception of apparently isolated facts and events; next comes the understanding of their interconnections and laws; finally comes the intuition of the structure and significance of the whole—the vision which sees all things in God, and God in all things.
Spinoza's theory of knowledge appears to make the ontolog ical assumption that reality is an interconnected system. Spinoza himself regarded it as an ultimate intuition. And his theory of knowledge was in some ways a justification of that view. To realize this it is necessary to grasp the fundamental distinction which Spinoza draws between "opinion" and "reason," or per ception and understanding. A percept or an image is, for Spinoza, something entirely different from an idea or concept. Conception or understanding is an activity which grasps interconnections, and has nothing to do with images as such. Perception and imagination, on the other hand, are concerned with images and not with connections. And the laws of these two kinds of activ ities are as different as are their objects. Perception, or imagina tion, is concerned with images and follows the laws of association; conception or understanding is concerned with connections and follows the laws of logic. Hence Spinoza's insistence that "we can not imagine God, but we can conceive Him" (Correspond ence, p. 289). Hence also Spinoza's rejection of Baconian empiricism. From observations of particulars as such it would be impossible, according to Spinoza, to derive laws or necessary connections. The laws or general truths of science rest, in the last resort, not on their correspondence with objects of percep tion, but on their harmonious interconnection in a system of truths. Spinoza, accordingly, dispenses with an external criterion of truth. "The true," he maintains, "reveals itself and the false." The ultimate test of truth is more truth or more knowledge, or the coherence of all that is known. The false or untrue betrays itself by its incoherence with what is already known. In fact, Spinoza for the most part regards ideas or concepts from the point of view of their adequacy rather than their truth, in order to avoid the suggestion of a merely external correspond ence such as is usually associated with the term "truth." Con cepts (or "ideas" in this sense) are acts of thought by which the laws and interconnections of things and events are appre hended. They are adequate in so far as they really enable us to
systematize a certain range of facts. In that case they are also true, for they agree with the facts. The primacy, however, is with the adequacy of the concept, because until we have the adequate concept we can not apprehend the facts in such a way that it can be said to agree with them, or to be true.
In the history of philosophy Spinoza was the first to elaborate the coherence theory of truth. In his time mathematics was the only science that could serve as a model of such a coherent system. Hence his addiction to the method of geometry. The significance of his use of this method has been misinterpreted. His sole aim was to express his philosophy in as coherent and objective a manner as possible. Two points should be noted in particular. In the first place, Spinoza did not suppose that science or philosophy can dispense with observation or experience. He fully realized the importance of experience in the very setting of the problems which science and philosophy seek to solve ; and it is known from his letters that he carried out many chemical and physical experiments. All that he insisted upon was that science involves much more than mere observation, that it needs concepts not derived from experience. It was his intention to write about scientific method, and to show that Bacon's ideas about it were inadequate; but this was one of several plans which he did not live long enough to carry out. The second point is that Spinoza had no delusions about the conclusiveness of the geometrical method. He himself had expounded the philosophy of Descartes in that method, although he thoroughly disagreed with it.
Above all it is important to note that, for Spinoza, the highest knowledge ("intuitive" or "clear" knowledge) is something much fuller and richer than the abstract assertions usually associated with the term knowledge. In the Short Treatise (p. 69 ed. Wolf) he describes it as "feeling and enjoying the thing itself." One must try to realize his meaning by thinking of what happens when a train of thought interests a thinker so deeply as to master him completely, and he gets so absorbed in the object of his thought as to identify himself with it. If we can conjure up all this vividly and warmly, then we may realize how Spinoza came to identify the highest "knowledge" with that "intellectual love of God" in which the individual realizes himself as part of the living Universe. In this state he does not merely picture reality in an external manner, but feels its very heart throb, and feels himself as part of it. But here we are on the verge of the mystical where all but the greatest poets cease to be articulate.