Context

Having divided perceptions into impressions and ideas, the author begins his lengthy examination of ideas. In the present section, he distinguishes between ideas of memory and ideas of imagination.

Background

For Locke, we have an idea of reflection whose object is a faculty of the mind he calls “retention,” or “the keeping of those simple ideas which from sensation or reflection it hath received” (Essay, Book II, Chapter 10). Memory is a “way of retention” which is “the power to revive again in our minds those ideas which, after imprinting, have disappeared, or have been as it were laid aside out of sight.” Locke compares it to a storehouse for our ideas. In the second edition of the Essay, he clarifies that the original perceptions are not literally stored in the mind, for they “cease to be anything when there is no perception.” Instead, the original perception is “revived” and accompanied by the further perception “that it has had them before.”

Berkeley mentions memory casually only twice in the Principles, but he takes some pains to distinguish imagination from sense. The imagination forms ideas by compounding or dividing, while memory “barely” represents ideas imprinted on the senses or perceived by attending to the passions (§3).

The ideas of Sense are more strong, lively, and distinct than those of the imagination; they have likewise a steadiness, order, and coherence, and are not excited at random, as those which are the effects of human wills often are, but in a regular train or series, the admirable connexion whereof sufficiently testifies the wisdom and benevolence of its Author. (§30).

The Treatise

1. As was seen in Section 1, experience shows that impressions which are present in the mind make another appearance there as ideas. There are two different ways in which this may occur. The first way is that of memory. In this case, the impression “in its new appearance” as an idea “retains a considerable degree of its first vivacity.” Because it retains a good deal of the force of the original impression, this appearance “is somewhat intermediate betwixt an impression and an idea.” The second way is that of imagination. All the vivacity of the original impression is lost, and the new appearance becomes “a perfect idea.” “’Tis evident at first sight, that the ideas of the memory are much more lively and strong than those of the imagination.” Also, the faculty of memory “paints its objects in more vivid colours, than any which are employ’d by” the imagination. The idea generated by memory “flows in upon the mind in a forcible manner,” while that generated by the imagination “is faint and languid.” Moreover, the idea of imagination is unstable: it cannot be preserved for any considerable amount of time in a steady and uniform way. This is a “sensible difference” between one kind of idea (that of memory) and another (that of imagination). This difference will be treated more fully in Book 1, Part 3, Section 5.

2. A second difference between the ideas of memory and those of imagination is that the ideas of memory preserve the same order and form of the original impressions, and are “in a manner ty’d down, . . . without any power of variation.” Ideas of imagination are not “restrain’d to the same order and form with the original impressions.”

3. When in memory there is a departure from the original order and form of the impressions, it is due to a defect or imperfection in the faculty of memory. The author uses an analogy between the narration of an historian and a faulty use of memory. For convenience, the historian may relate a sequence of events in the wrong order. But if he “be exact,” he will revise his narration to preserve the proper time-sequence. Similarly, we may get the sequence of events wrong when it comes to “our recollection of those places and persons, with which we were formerly acquainted.” The implication of the author is that if we are to be “exact” in our recollections, we would also make the required corrections. The author concludes the paragraph with a general principle, which is that the chief function of memory is to preserve the order and position of the simple ideas, corresponding to the order of the simple impressions of which they are copies, rather than to preserve those ideas themselves. The author spares the reader from a review of the phenomena that support this principle, since it consists of “such a number of common and vulgar phænomena.”

4. A second principle concerns the imagination: that it is free “to transpose and change its ideas.” This is confirmed without question by the fictional stories to be found in poetry and romances. “Nature there is totally confounded, and nothing mention’d but winged horses, fiery dragons, and monstrous giants.” The freedom of the imagination is supported by the observation that the original impressions which give rise to our ideas are all (if different) “perfectly” separable from one another. If the impressions can be separated from one another, the corresponding ideas may be separated from one another as well, which allows the imagination to combine them as it will. [Note that this is the first appearance of a key principle invoked later in the Treatise. In Section 7, the principle is stated in its full generality: “whatever objects are different are distinguishable, and whatever objects are distinguishable are separable by the thought and imagination.” In the present case, the “objects” are ideas, which when different are distinguishable by the imagination, from which it follows by the principle that they are separable by the imagination.] On the other hand, some ideas are complex, and complex ideas may be dis-assembled (or, in the language of Section 1, “separated”) into simple ideas, “whenever the imagination perceives a difference among ideas.” [Again, what is different is distinguishable and what is distinguishable is separable.] This allows the imagination to re-assemble, in any connection it pleases, the simple ideas that were separated out of the complex ideas.

The Enquiry

In the Enquiry concerning Human Understanding, Hume has no explicit discussion of memory. He frequently uses the conjunctive phrase “memory or senses” in contrast to imagination. [See, for example, Section 5.] Presumably this is because he thinks of both memory or sense as objective, as opposed to the arbitrary inventions of the imagination. At other times, such as in Section 3, Hume groups memory with imagination in contrast to the senses, in that both concern ideas, and both are governed by certain principles of association of ideas.