Book: De Homine

Overview
De Homine (1658) presents a materialist, mechanistic account of human beings that extends Hobbes's natural-philosophical method to psychology, language, and social behavior. Hobbes treats the human mind as a system of motions and interactions governed by physical causes, describing sensation, imagination, thought, and passion in terms of bodily processes. The book reads as a bridge between his earlier natural philosophy and his political arguments, showing how bodily causes of cognition and desire lead to social outcomes that require political organization.

Mind, Body, and Motion
Hobbes insists that every mental phenomenon has a bodily basis: sensory input arises from external motions striking the senses, imagination is a faint or decaying continuation of sense impressions, and reasoning is the successive comparison of names and ideas according to experience. He explains perception, retention, and memory through the persistence and decay of motion in the nervous system, using contemporary notions of "animal spirits" and nervous conduits. Liberty and necessity are treated within the same causal framework: choice is a motion initiated by competing passions and directed by deliberation, while what people call freedom is compatible with deterministic chains of causes.

Passions and Human Motivation
A sustained part of De Homine analyzes the passions as the primary drivers of human action. Desire, aversion, hope, fear, love, and hate are described as motions arising from bodily appetites and aversions; social behaviors flow from the interplay of these passions. Hobbes emphasizes the roles of self-preservation, desire for commodities, and pursuit of power and glory, showing how these motivate competition and conflict in the absence of common authority. Moral terms such as good and evil are recast as names for things desired or avoided, rooting ethics in psychology rather than abstract moral qualities.

Language, Signs, and Reason
Language receives careful attention as the artificial instrument that enables complex reasoning and social coordination. Hobbes analyzes words as "signs" that stand for internal motions or external objects and argues that the invention of speech makes abstract reasoning and civil cooperation possible. By clarifying how names, definitions, and syllogisms function, he seeks to remedy confusion caused by ambiguous language and to show how common speech underlies scientific and political discourse. Reason thus becomes a calculative process of combining signs according to agreed rules.

Political Implications
Although primarily psychological and physiological, De Homine repeatedly connects human nature to political conclusions. Hobbes portrays the state of nature as a condition where competing passions and equal capacities produce insecurity; the need for peace and the avoidance of violent death motivate individuals to authorize a sovereign. The mechanistic account of human desires supports his broader claim that durable social order requires a common power to direct collective behavior and resolve conflicts that arise from natural appetites and fears.

Method and Significance
De Homine exemplifies Hobbes's commitment to applying a unified, scientific method across natural and moral domains: explain phenomena by appeal to motion, matter, and causal laws. The book influenced later materialist and empiricist thought by advancing a naturalistic psychology that treats cognition and language as amenable to physiological and logical analysis. Its bold reduction of mental life to corporeal processes provoked controversy, especially for its challenges to scholastic and theological accounts of the soul, but it also helped shape modern debates about mind, language, and the foundations of political obligation.