Chapter 6: Of the Interior Beginnings of Voluntary Motions, commonly called the Passions. And the Speeches by which they are expressed.
Chapter 7: Of the Ends, or Resolutions of Discourse
Chapter 8: Of the Vertues commonly called Intellectual; and their contrary Defects
Chapter 9: Of the Severall Subjects of Knowledge
After his scenario for the transfer of motion from object to object and ultimately into living organisms, Hobbes elaborates the nature of motion as it is manifested in animals. Hobbes acknowledges two types of motion peculiar to animals: "Vital" and "Voluntary." Vital motions are innate and automatic to all animals, and continue throughout life; they include the flow of blood, breathing, digestion, excretion, and the like. Voluntary motions are active and directed, such as walking, speaking, and the moving of the limbs.
Hobbes considers the causal factors that precipitate voluntary motions, the motions that eventually progress into directed actions. These causal motions are thoughts and imaginations. Of them Hobbes writes, "[These] small beginnings of Motion, within the body of Man, before they appear in walking, speaking, striking, and other visible actions, are commonly called ENDEAVOUR." Hobbes subsequently defines endeavor: "This Endeavour, when it is toward something which causes it, is APPETITE, or DESIRE . . . And when the Endeavour is fromward something, it is generally called AVERSION." Appetites and aversions, like everything in Hobbes's mechanistic universe, are discovered to be the product of transferred motion, and the interplay of appetites and aversions constitutes Hobbes's depiction of human nature. To recapitulate: Hobbes's derivation of human appetites and aversions from the elementary kinetics of the universe and the impact of material bodies on the human form means that human nature itself is the direct mechanic product of physical processes.
Hobbes details a large roster of the appetites and aversions that exist in human beings, some "born with men" (caused by internal motions), some "proceed[ing] from Experience" (caused by external motions). From these two categories of appetite and aversion arise all the "Passions" known in human natures; every passion from delight and ambition to anger and curiosity derives from some configuration of appetite and aversion. Even the metaphysical categories of good and evil issue originally from appetite and aversion, for Hobbes writes that "the object of any mans Appetite or Desire; that is it, which he for his part calleth Good: And the object of his Hate, and Aversion, Evill."
When a person initiates a train of thoughts in order to judge something "Good" or "Evil"--that is, in order to ascertain whether he or she has an "appetite" or "aversion" to that thing--the person is said to "Deliberate." The end of deliberation, the conclusion drawn from the consideration of good or evil consequences, the decision to act or not to act, is called the "Will." When deliberation is put into speech, the building of consequences and conclusions is similar to the process of constructing philosophically true speech (Hobbes described this process in the previous section). However, Hobbes points out that deliberation is purely subjective to the person deliberating, and therefore cannot be considered a science.
Science is, Hobbes repeats, the "knowledge of the consequence of words" for which definitions have been rigidly established. Hobbesian science yields knowledge that is true for all speakers of the shared language and is therefore objective. If the foundation of discourse is not a shared set of definitions, then the conclusions derived from such discourse are called "Opinion." And if the foundation of discourse is even narrower--if it is constituted of the words of some particular person or text--then the resolution of discourse is called "Belief" or "Faith." By giving the examples of opinion and faith, Hobbes shows that all knowledge, including scientific knowledge, is conditional and that "no Discourse whatsoever, can End in absolute knowledge of Fact, past, or to come." But Hobbesian scientific discourse, based on definitions, nevertheless provides knowledge that is secure and trustworthy, because it is based not on opinion or faith, but on a universal sociological determination of first principles.