The Philosophical Review/Volume 1/Summary: Kappes - Die Erkenntnisslehre des Thomas Hobbes
Hobbes embodies in his philosophy standpoints that are quite opposed to each other. First, he sets up a method analogous to that of geometry, then he holds that all knowledge is derived from sense-perceptions, and finally establishes motion as the principle underlying all phenomena. His method is, therefore, not inductive like Bacon's, but hypothetical-deductive. His attempt to establish science on a basis as firm as that of mathematics ends in nominalism; logic becomes for him a doctrine of naming, thinking an art of reckoning with names. Had he drawn the conclusions of his sensualism, the entire corporeal world would have become an illusion. But his strict adherence to the materialistic principle according to which all phenomena are forms of motion, prevents him from ending as a phenomenalist. The philosophy of Hobbes fails to appreciate the fact that our knowledge is the product of two factors, the subjective and the objective. As an admirer of mathematical reasoning he aims at ultimate principles that are universal and necessary. This leads him to nominalism. If you accept his principle that concepts are merely names, there can be no objection to his conclusions. But the concept is not only a general name, it is a general thought, which is ascribed to objects, and therefore has objective significance. It is a general idea that has objective reality. If concepts are mere names, it is inconsistent in Hobbes to base his philosophy on such notions as body, motion, and extension. Furthermore, his theory of sensation cannot explain how motion is suddenly transformed into sensation, nor even how the thought-process is derived from sensation. In spite of all contradictions, however, one thorough-going, normative principle prevails in his philosophy. It is that of motion.
Hobbes cannot be designated as a follower of Bacon, though he agrees with him in his general tendency to base the knowledge of nature on experience. He is rather to be reckoned among the pupils of Descartes, who also constructs the universe with matter and motion. Hobbes goes further than Descartes in his endeavor to explain mechanically even psychical occurrences. We may say that Hobbes was the first to consider the question as to the possibility of scientific knowledge; he is the originator of empirical epistemology. Locke's sensualism and Berkeley's phenomenalism are already implicitly contained in his doctrine of sensation. To him also physiological psychology owes its origin.