Empiricist epistemology – Thomas Hobbes

This post will make more sense if the reader reads this first.

Empiricist epistemology

Thomas Hobbes began several major works of political philosophy by first discussing the nature of sensation and its underlying significance for understanding political matters. Similarly, David Hume’s An Enquiry concerning Human Understanding is simply that, an investigation of human cognition. Despite the empiricist’s disagreement with Descartes’ claims that intuition was the origin of ideas and that human knowledge was guided principally by the pure light of reason, and arguing instead that ideas originated from sensation, they nonetheless began their philosophical inquiry with epistemological questions, placing them within the framework of traditional epistemology.

Further, despite Hobbes and Hume’s empiricism, they nonetheless adopted Descartes’ mathematical foundationalism. Hobbes and Hume both began with the perception of external objects through sensation, recognizing the role of calculative, cognitive processes such as imagination and understanding along the way, but ultimately attempted to account for the rest of human knowledge through deductive procedure modeled on the methods of mathematics similar to those of Descartes.

Thomas Hobbes

For Hobbes, these were two kinds of knowledge: sensation and the results of ratiocination, or reckoning, about our sense knowledge.

Sensation is a motion in the sense organ produced by the power, or motion, of an external object, which through the nerves and membranes of the body causes a further motion in the brain. Motions in the brain are called images, which are retained in the imagination and memory. This store of imagination and memory is called experience. Sensation is the origin of single, discrete thoughts while a train of such thoughts is either the result of the observance or creation of a succession of connected thoughts. These trains of thought compose mental discourse.

Hobbes calls human thinking by various names: ratiocination, reckoning, reasoning, or computation. Regardless of the term used, his meaning is the same, namely that man’s cognition proceeds by means of adding and subtracting from the thoughts received through sensation.

By Ratiocination, I mean computation. Not to compute, is either to collect the sum of many things that are added together, or to know what remains when one thing is taken out of another. Ratiocination, therefore, is the same with addition and subtraction; and if any man add multiplication and division, I will not be against it, seeing multiplication is nothing but addition of equals one to another, and division nothing but a subtraction of equals one to another, as often as is possible. So that all ratiocination is comprehended in these two operations of the mind, addition and subtraction. (1)

Elsewhere, Hobbes refers to adding and subtracting as synthetical and analytical methods, respectively. (2)

Human knowing, then proceeds in the following fashion for Hobbes. Man starts from his sensation of external objects. In order to acquire knowledge about these objects, he must understand the causes of the objects. He reasons or reckons analytically, subtracting away parts and aspects of the object, in order to discover the most universal elements of those objects, which Hobbes calls first principles, or definitions, of any further ratiocination. Hobbes provides at least one concise example of how he understands this process to work:

For example, if there be propounded a conception or idea of some singular thing, as of a square, this square is to be resolved into a plain, terminated with a certain number of equal and straight lines and right angles. For by this resolution we have these things universal or agreeable to all matter, namely, line, plain, (which contains superficies) terminated, angle, straightness, rectitude, and equality; and if we can find out the causes of these, we may compound them altogether into the cause of a square. (3)

These universal elements are the accidents common to all bodies, or all matter, which are caused, according to Hobbes, by motion. (4) He calls reasoning about the elementary motion which causes universals geometry and reasoning about the motion of sensible qualities physics. These are followed by reasoning about motion in the mind called moral philosophy and motion in the body politic called civic philosophy.

Like Descartes, the whole of Hobbes’ theory of knowledge is a foundationalist strategy modeled upon the methods of mathematics, meaning that the ideal procession of cognitive steps upon which all human knowledge is built is modeled upon a generalized mathematical methodology. The other feature of mathematical foundationalism is that some ideas, or beliefs, are basic and other, non-basic beliefs are derived from the basic ones, which is also true of Hobbes’ epistemology.

On several occasions, Hobbes holds up geometry as the paradigmatic discipline. In the square example above from De Corpore, all the terms he gives as examples of universal things (“line”,”plain”, “terminated”, “angle”, “straightness”, “rectitude”, “equality”) are taken from geometry. In Leviathan, Hobbes’ low opinion of philosophers is similar to Desacrtes’, for which he provides a familiar diagnosis given the past and current philosophical absurdity:

But this privilege [reckoning], is allayed by another; and that is, by this privilege of absurdity; to which no living creature is subject, but man only. And of men, those are of all most subject to it, that profess philosophy. For it is most true that Cicero saith of them somewhere; that there can be nothing so absurd, but may be found in the books of philosophers. And the reason is manifest. For there is not one of them that begins his ratiocination from the definitions, or explications of the names they are to use; which is a method that hath been used only in geometry; whose conclusions have thereby been made indisputable. (5)

While Hobbes does not have the same confidence in human reasoning that Descartes does, he nonetheless holds the methods of mathematics, specifically arithmetic and geometry, up as the ideal method according to which human reasoning ought to proceed.

See next post.

Notes:

1. Thomas Hobbes, De Corpore, I, 2.
2. ibid., II, 3.
3. ibid., VI, 1.
4. ibid., VI, 4.
5. Thomas Hobbes, Leviathan, I. V. 7.