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
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.