A Treatise of Human Nature / Being an Attempt to Introduce the Experimental Method Into Moral Subjects; and Dialogues Concerning Natural Religion

by David Hume

This he will passively observe.

8. This ‘thinking thing,’ then, as he finds it in himself, the philosopher, according to Locke, has merely and passively to observe, in order to understand the nature of knowledge. ‘I could look into nobody’s understanding but my own to see how it wrought,’ he says, but ‘I think the intellectual faculties are made and operate alike in most men. But if it should happen not to be so, I can only make it my humble request, in my own name and in the name of those that are of my size, who find their minds work, reason, and know in the same low way that mine does, that the men of a more happy genius will show us the way of their nobler flights.’ (Second Letter to Bishop of Worcester.) As will appear in the sequel, it is from this imaginary method of ascertaining the origin and nature of knowledge by passive observation of what goes on in one’s own mind that the embarrassments of Locke’s system flow. It was the function of Hume to exhibit the radical flaw in his master’s method by following it with more than his master’s rigour.

Is such observation possible?

9. As an observation of the ‘thinking thing,’ the ‘philosophy of mind’ seems to assume the character of a natural science, and thus at once acquires definiteness, and if not certainty, at least plausibility. To deny the possibility of such observation, in any proper sense of the word, is for most men to tamper with the unquestioned heritage of all educated intelligence. Hence the unpalatability of a consistent Positivism; hence, too, on the other side, the general conviction that the Hegelian reduction of Psychology to Metaphysics is either an intellectual juggle, or a wilful return of the philosophy, which psychologists had washed, to the mire of scholasticism. It is the more important to ascertain what the observation in question precisely means. What observes, and what is observed? According to Locke (and empirical psychology has never substantially varied the answer) the matter to be observed consists for each man firstly in certain impressions of his own individual mind, by which this mind from being a mere blank has become furnished—by which, in other words, his mind has become actually a mind; and, secondly, in certain operations, which the mind, thus constituted, performs upon the materials which constitute it. The observer, all the while, is the constituted mind itself. The question at once arises, how the developed man can observe in himself (and it is only to himself, according to Locke, that he can look) that primitive state in which his mind was a ‘tabula rasa.’ In the first place, that only can be observed which is present; and the state in question to the supposed observer is past. If it be replied that it is recalled by memory, there is the farther objection that memory only recalls what has been previously known, and how is a man’s own primitive consciousness, as yet void of the content which is supposed to come to it through impressions, originally known to him? How can the ‘tabula rasa’ be cognisant of itself?

Why it seems so.

10. The cover under which this difficulty was hidden from Locke, as from popular psychologists ever since, consists in the implicit assumption of certain ideas, either as possessed by or acting upon the mind in the supposed primitive state, which are yet held to be arrived at by a gradual process of comparison, abstraction, and generalisation. This assumption, which renders the whole system resting upon the interrogation of consciousness a paralogism, is yet the condition of its apparent possibility. It is only as already charged with a content which is yet (and for the individual, truly) maintained to be the gradual acquisition of experience, that the primitive consciousness has any answer to give to its interrogator.

Locke’s account of origin of ideas.

11. Let us consider the passage where Locke sums up his theory of the ‘original of our ideas.’ (Book II. chap. i. sec. 23, 24.) ‘Since there appear not to be any ideas in the mind, before the senses have conveyed any in, I conceive that ideas in the understanding are coeval with sensation; which is such an impression, made in some part of the body, as produces some perception in the understanding. It is about these impressions made on our senses by outward objects, that the mind seems first to employ itself in such operations as we call perception, remembering, consideration, reasoning, &c. In time the mind comes to reflect on its own operations about the ideas got by sensation, and thereby stores itself with a new set of ideas, which I call ideas of reflection. These impressions that are made on our senses by outward objects, that are extrinsical to the mind; and its own operations, proceeding from powers intrinsical and proper to itself, which, when reflected on by itself, become also objects of its contemplation, are, as I have said, the original of all knowledge.’

Its ambiguities (a) In regard to sensation.

12. Can we from this passage elicit a distinct account of the beginning of intelligence? In the first place it consists in an ‘idea,’ and an idea is elsewhere (Introduction, sec. 8) stated to be ‘whatsoever is the object of the understanding, when a man thinks.’ But the primary idea is an ‘idea of sensation.’ Does this mean that the primary idea is a sensation, or is a distinction to be made between the sensation and the idea thereof? The passage before us would seem to imply such a distinction. Looking merely to it, we should probably say that by sensation Locke meant ‘an impression or motion in some part of the body;’ by the idea of sensation ‘a perception in the understanding,’ which this impression produces. The account of perception itself gives a different result. (Book II. chap. ix. sec. 3.) ‘Whatever impressions are made on the outward parts, if they are not taken notice of within, there is no perception. Fire may burn our bodies with no other effect than it does a billet, unless the motion be continued to the brain, and there the sense of heat or idea of pain be produced in the mind, wherein consists actual perception.’ Here sensation is identified at once with the idea and with perception, as opposed to the impression on the bodily organs. [1] To confound the confusion still farther, in a passage immediately preceding the above, ‘Perception,’ here identified with the idea of sensation, has been distinguished from it, as ‘exercised about it.’ ‘Perception, as it is the first faculty of the mind exercised about our ideas, so it is the first and simplest idea we have from reflection.’ Taking Locke at his word, then, we find the beginning of intelligence to consist in having an idea of sensation. This idea, however, we perceive, and to perceive is to have an idea; i.e. to have an idea of an idea of sensation. But of perception again we have a simple or primitive idea. Therefore the beginning of intelligence consists in having an idea of an idea of an idea of sensation.