The young Thomas Hobbes worked closely with Bacon during the latter's elder years as Lord Chancellor. He also visited Galileo during the eminent scientists period of house arrest. Although, as you can see, Hobbes' approach to knowledge shows some affinity to Baconian concepts, Hobbes never gave the elder any credit. Probably for very great reason, because Hobbes, like Galileo and unlike Bacon, turned to mathematics. While bacon was interested only in the practical effects of scientific advancement, Hobbes was more interested in science as a source of knowledge. Thus, as we look at Hobbes' approach to induction we must restrain our tendency to credit Bacon. Hobbes spent some time in France and obviously became aware of the Cartesian idea that the ultimate source of knowledge would necessarily be through a method of thought. Thus Hobbes approach was to understand the role of reasoning in man's search for knowledge.

When a man reasoneth, he does nothing else but conceive a sum total, from the addition of parcels; or conceive a remainder, from subtraction of one sum from another; which, if it be done by words, is conceiving of the consequence of the names of all the parts, to the name of the whole; or from the names of the whole and one part, to the name of the other part... For reason, in this sense, is nothing but reckoning, that is adding and subtracting, of the consequences of general names agreed upon for the marking and signifying of our though.

Bacon's thought aimed toward the practicality of science. He rejected out of hand the mathematical approach. This statement is Hobbes' attempt to put mathematical reason on a practical basis. He said that reasoning was not instinctive to man, nor was it developed by experience. We acquire it through industry. First we must learn to define, then to use an orderly method of proceeding from names to statements to syllogisms. Science, he said was knowledge of the consequences of names, but names can only be known through definition.

Perhaps it will make more sense if we consider the problems that Galileo had to overcome before he could develop his experimental method. Consider the laws of motion concerning a falling object. Obviously he was not able to perform an experiment with a ball falling from an infinite height in a frictionless atmosphere. Since he lacked accurate time measuring devices, his measurements were crude compared with our twentieth century equipment. Yet he was able to develop laws which were exact, not approximations. More importantly, they pertained to objects falling in a frictionless as well as a normal atmosphere. These were laws which regulate things and events beyond experience. Aristotelian physics, as accepted in his day was based on the observation of actual objects and from pure reasoning about them. They thus pertained only to what would be expected from the reasons behind the actions of falling bodies. There is a step of reasoning involved in Galileo's method that violated Aristotelian assumptions. Galileo had to imagine, to perform a thought experiment, concerning what would happen if in fact there were such a thing as a frictionless atmosphere. A frictionless atmosphere not a possible experience, it is a concept beyond all possible experience. Not only that, since he could not measure small time intervals he was forced to use inclined planes rather than simply dropping objects. There is no direct experienced relationship between inclined planes and a frictionless atmosphere.

That a moving object in a frictionless atmosphere will continue to move at a constant velocity and direction until something prevents it from doing so cannot be determined directly by observation. Even more difficult is the idea that the speed of a falling object is irrelevant to its weight. These concepts are not intuitively developed from experience as Aristotle suggested we develop all of our knowledge. Each case had to be considered first as a hypothesis. This hypothesis would then be tested by a thought experiment and only following that could actual experiments be developed which would confirm or refute the hypothesis. Just as important is the idea that the laws developed through this process are inviolate. They do not depend on circumstances. They apply equally to everything. They are universal and unchanging. They are extracted from the sensual world but exist only in the world of pure thought.

In order for Galileo to determine that the laws he found were in fact inviolable, he had to take his mind experiment and express it as a set of mathematical functions. Mathematical functions are unchanging entities and thus are forms of pure knowledge. These he could apply to the results of his experiments and thus determine the validity of his hypotheses. But keep in mind that the only thing that was being validated was the concepts developed in Galileo's mind because reasoning only applies to mental propositions. It does not apply to things or to the actions of things.

A circle, as seen by geometricians, is not something found in nature. It is an abstract structure created by the motion of a point around a center. Thus, science began essentially as a study of motion, Hobbes applied his theory of knowledge to the events of human beings by first recognizing that names are determined entirely by definitions. Definitions, like mathematical functions, are created by men but determine completely what it is that men use them to refer to. Thus, a definition used in this sense is equivalent to a Euclidean axiom. Utilizing the concept of definitions, and the laws of nature learned from these, he believed he could become the Euclid of civil science. It will become important when we come to Hobbe's political theory that we understand that his theory of knowledge, developed around pure deduction from definitions was to make political theory just as exact as Galileao's physical laws. This point of view is important because it was the background out of which John Lock was able to develop a new approach to knowledge that was to separate England from the continent intellectually, at the same time that it transformed Philosophy and the Western view of the world.