OVERVIEW A Treatise of Human Understanding was first published in 1738. Hume divided the book into three parts. The first book discussed the nature and mechanism of understanding. In it, Hume explores thought, the foundation of belief, and the place of skepticism. The second book focuses on the passions, investigating the mechanism and function of both emotion and free will. The third book is centered on morality. In this section, Hume examines the roots of the moral impulse and the nature of moral ideas such as justice, obligations and benevolence.
Hume enters the work with an argument for the validity of empiricism. He begins with the premise that all knowledge is based upon sense experience. He then demonstrates that all complex ideas are formed from simple ideas, and that all simple ideas enter into the consciousness through the vehicle of sense impressions. This line of reason equates ideas with experiences and subjects them both to the same measures of verification and validation.
Another key piece to Hume’s argument is his definition of “matters of fact.” Hume describes matters of fact as aspects of understanding that must be experienced. Reason and instinct are, by this definition, unable to provide us with factual validation. This is the foundation that allows Hume to critically examine metaphysical systems and concepts. The God concept and beliefs related to the soul are beyond sense experience and verification. Therefore, they are meaningless questions in epistemological terms. We do not have the capacity to evaluate the in the light of experience.
Hume next uses the empiricist definition of fact to investigate the nature of the concepts of space, time and mathematics. In essence, we have no direct experience of space, but rather only of objects we encounter. None of these objects has a quality which can be defined as space. Similarly, we have no direct experience of time. We only recognize and form impressions of events we experience. Each of these concepts, therefore, is an illusion of reason. We cannot rest upon it if we are seeking sure and certain knowledge. Hume examines mathematics from the angle of infinite divisibility. He shows that while in mathematical terms there is no limit to the extent to which we are able to divide numbers, at a certain point in the division, the parts become so small that we are unable to 6
