Context

In his account of causal inference, the author has isolated three features that call for explanation: the original impression (of the cause), the transition to a new idea (of the effect), and the qualities of the resultant idea. Having completed his discussion of the second factor, he now turns to the third. In particular, he wants to explain belief as the salient quality of the idea.

Background

The stated goal of Locke’s Essay was “to inquire into the original, certainty, and extent of human knowledge, together with the grounds and degrees of belief, opinion, and assent . . . ” (Book I, Chapter 1, Section 4). Locke distinguished sharply between belief and knowledge, holding that belief is reserved for propositions which are only probable or likely to be true. “The entertainment the mind gives this sort of propositions is called belief, assent, or opinion, which is the admitting or receiving any proposition for true, upon arguments or proofs that are found to persuade us to receive it as true, without certain knowledge that it is so” (Book IV, Chapter 15, Section 3). Thus Locke took belief to be, as we would now say, a propositional attitude.

The Treatise

1. The goal of this section is to provide an account of “the nature of belief, or the qualities of those ideas we assent to.” The belief “of” an object contains the idea of that object as an essential part, but this idea is not the whole of the belief.

2. The author begins his description of the remaining component of belief by recounting two things he takes to be “evident.”

• The conclusions of reasoning from cause to effect or from effect to cause concern “the existence of objects or of their qualities,” which are matters of fact.
• There is no distinction between the idea of existence and that of any object, so to conceive an object as existing is the same as simply to conceive it. [See Book I, Part 2, Section 6.]

3. One way to put the question is to look for the difference between believing something and not believing (“disbelieving”) it. For example, the author does not believe that Julius Caesar died in his bed. If someone were to propose this proposition, his meaning would be understood by the author despite his lack of belief (“incredulity”). “My imagination is endow’d with the same powers as his; nor is it possible for him to conceive any idea, which I cannot conceive; or conjoin any, which I cannot conjoin.” With respect to propositions proved by intuition or demonstration, when a person believes, he is necessarily determined to conceive the idea in the way it is described in the proposition. But this does not apply to cases of reasoning from causation. One can conceive the object either incredulously (not believing) or credulously (believing).

4. The author grants that when two people disagree over a proposition they both understand, the presence or absence of belief must make some difference in the conception of the object in question. There are many ways to vary the ideas in our conception (mingling, uniting, separating, confounding) but belief requires that there be a single principle “which fixes one of these different situations.” Because the principle cannot add anything to the ideas present before belief, it “can only change the manner of our conceiving them.”

5. The only way in which the manner of conceiving an object through ideas can vary is with respect to its “force and vivacity.” The reason is that ideas are copies of impressions and add nothing to what appears in the impression. If the idea were to differ from the impression, it would not be a copy of it any more. So a color may be presented in a more lively way (e.g., as brighter) in an impression than in an idea of it, “But when you produce any other variation, ’tis no longer the same shade or colour.” The author concludes that the only thing that belief could add to an idea is a greater degree of force or vivacity, so he defines belief (or opinion) as “a lively idea related to or associated with a present impression.”

Footnote. The author discusses a systematic error made on the part of scholastic logicians which “has become a kind of establish’d maxim, and is universally receiv’d by all logicians.” The error lies in the distinction between three kinds of acts of the understanding and the way they are described.

• Conception: “the simple survey of one or more ideas,”
• Judgment: “the separating and uniting of different ideas,”
• Reasoning: “the separating and uniting of different ideas by the interposition of others, which show the relation they bear to each other.”

6. A summary of the argument beginning in Section 4 is given. An impression of one object is the starting point of any inference from its existence to that of another. Otherwise, an infinite regress of causes would have to be generated, which is impossible for the human understanding. Reason does not inform us of the existence of any thing, so custom or a principle of association is required to explain the transition from the impression to the idea of its cause or effect. Belief is a way of conceiving an idea, and the only available difference between belief and non-belief is the vivacity of the idea. So “it follows upon the whole that” belief is a lively idea that is produced by the relation of that idea to the given impression.

7. [Appendix. Prior to the author’s discovery, “this operation of the mind, which forms the system of any matter of fact, seems hitherto to have been one of the greatest mysteries in philosophy,” though no one was aware of how difficult it is to explain it. The author himself struggles to describe it properly, even when he thinks he understands belief perfectly. His “induction” makes it very evident that belief is an idea distinct from fiction due to the manner in which it is conceived. But as it is hard to find words that describe this way of conceiving, he is “oblig’d to have recourse to every one’s feeling, in order to give him a perfect notion of this operation of the mind.” The two kinds of ideas feel different, and the author tries to capture the difference in this feeling using words such as “superior force, or vivacity, or solidity, or firmness, or steadiness.” These terms seem quite unphilosophical, but they do mark out “an act of the mind, which renders realities more present to us than fictions, causes them to weigh more in the thought, and gives them a superior influence on the passions and imagination.” This, so to speak, operational definition is all that matters, and the terms used to describe it are irrelevant. The imagination is capable of presenting conceptions to the mind in all sorts of ways, but it cannot reach belief. So belief does not consist in “the nature and order of our ideas,” but instead a the way of conceiving ideas and how they feel to the mind. Belief “gives [ideas of judgment] more force and influence, makes them appear of greater importance; infixes them in the mind; and renders them the governing principles of all our actions.”]

8. The author asserts that “this definition will also be found to be entirely conformable to every one’s feeling and experience.” There is nothing more evident than the difference between the ideas believed, which are “more strong, firm, and vivid,” and ideas merely imagined, “the loose reveries of a castle-builder.” If a reader treats one book as a fable and another as a “true history,” the same ideas are received, and in the same order, and the author’s meaning is understood in the same way. But the testimony of the author of the book has a different influence, in that one relates more deeply to the characters. The only way that fiction can even be entertaining is due to the “style and ingenuity of the composition.”

The Enquiry

The main discussion of belief in the Enquiry occurs in Part II of Section 5. In Part I, Hume arrived at the conclusion that All belief of matter of fact or real existence is derived merely from some object, present to the memory or senses, and a customary conjunction between that and some other object. The process of belief-formation is said to be instinctive and not rational. But the nature of this belief, and of the customary conjunction, whence it is derived, can be explored further. This exploration constitutes the body of Part II, which Hume notes can be skipped without detriment to the understanding of the rest of the Enquiry. He begins there by stating that the only difference between a belief and a fiction of the imagination is that the former feels different from the latter. The feeling would be very difficult, if not impossible, to define, but it can be described. Belief gives the ideas of judgment, as opposed to the fictions of the imagination, more weight and influence; makes them appear of greater importance; enforces them in the mind; and renders them the governing principle of our actions. We are told in Section 6 that the nature of belief and opinion is constituted by a measure of “reliance or security.” The account of belief found in the Treatise, “that belief is nothing but a firmer and stronger conception of an object than what attends the mere fictions of the imagination,” is proposed only to explain what Hume called in the Treatise “the probability of chances” (Book I, Part 3, Section 11).