AN ESSAY ON THE ACADEMICAL OR SCEPTICAL PHILOSOPHY, AS APPLIED BY MR. HUME TO THE PERCEPTION OF EXTERNAL EXISTENCE
Section I. The Question stated
1The question intended to be investigated in the following pages is thus stated in the Treatise [of] Human Nature,5 "Why we attribute a continued existence to objects even when they are not present to the senses?"6 And, "why we suppose them to have an existence distinct from the mind, i.e. external in their position, and independent in their existence and operation?"7
Mr. Hume argues at great length, that it is not by means either of the "senses, 2or of reason;" that "we are induced to believe in the existence of body;" but that we gain the notion entirely by an operation of the "imagination" which has "a propensity to feign the continued existence of all sensible objects, and as this propensity arises from some lively impressions on the memory, it bestows a vivacity on that fiction, or in other words, makes us believe the continued existence of body". It is not my intention to analyze Mr. Hume's pg 32reasoning on this subject, which I conceive to be altogether erroneous, and which it would be very tedious to examine; I prefer, therefore, answering the question as it stands, according to my own views of it, setting down what experience and reflection suggest to my mind as the operations of nature in this matter; and I shall endeavour to point out what complication of objects, and what arrangement of them is necessary towards that result which appears to us from its familiarity and constancy of appearance, perfectly simple and 3easy to be understood. But first, I shall shortly observe, that Mr. Hume's error in general is similar to that in the essay on "necessary connexion,"8 viz. of substituting "imagination" and "vivacity of thought," as a ground of belief, instead of "reason." "An idea," says Mr. Hume, "acquires a vivacity by its relation to some present impression,"9 and this at once, according to him, forms the whole ground upon which our "belief" rests, of the necessity there is, that similar effects should flow from similar causes, and that objects should continue to exist unperceived. It is my intention to show here, as upon a former occasion, that as the very act of reasoning consists in drawing out to observation the relations of things as they are included in their juxtaposition to each other; so upon this question, concerning our "knowledge of the existence of body," it is reason, which taking notice of the whole of our perceptions, and of their mutual relations, affords those proofs "of body" which first generate, and after examination will substantiate, the belief of its existence.
4The question proposed in the Treatise is resumed in the essay on "the Academical or Sceptical Philosophy [i.e., Enquiry 12] thus: "By what argument can it be proved, that the perceptions of the mind must be caused by external objects?"10 and "reason" is there said also, "not to have it in her power to find any convincing argument to prove, that the perceptions are connected with any external objects;"11 but that on the contrary, "the slightest philosophy teaches us, that the senses are not able to produce any immediate intercourse between the mind and the object; for the table which we see seems to diminish as we remove further from it, but the real table which exists independent of us suffers no alteration."12
It will be seen by any intelligent reader, accustomed to discussions of this sort, that the consideration of the question, as stated in Mr. Hume's treatise, pg 33and the notions I have thence deduced will contain a doctrine capable of answering 5any errors of Dr. Berkeley's13 on the same subject, whose opinions, which originally had been intended as the foundation of the most secure belief in Deity, Mr. Hume has endeavored to convert, by an enlarged application of them, (by an induction of the non-existence of mind as well as matter,) into a source of universal scepticism.14
The incompleteness of Dr. Reid's answer to these authors, will also be perceived in the course of the argument here used against them; it will be seen that he cuts the knot instead of untying it,15 by referring a belief in the opinion "there is body" only to "natural instinct."16 This notion can never satisfy us, as affording either the reason for our belief, or as detailing to us the manner in which it arises.
1. Sensation a generic term, &c.
2. Question restated.
3. Generally answered and subdivided into three parts for further consideration.
61. In the discussion of this subject ("as to our knowledge of the existence of body,") I mean to follow the example of Dr. Berkeley in the use of the word sensation chiefly, instead of perception; because it is a generic term, comprehending every consciousness whatever. Dr. Reid17 is most unphilosophical in supposing perception to be a power of the mind independent of sensation, and [in supposing] that it can be contradistinguished from it;18 whereas, although every sensation may not be the perception of an exterior object, acting on either of the five organs of sense, yet there can be pg 347no perception of such objects without that inward act of consciousness, which, as a consciousness, is in truth a sensation of the mind. When it is apprehended that all we know must be by means of consciousnesses, or sensations, then will be the time to analyze their various classes, to examine their relations, to notice their peculiarities, in order to discover by what means it is we come to the belief of non-sentient existences. I know, indeed, that it is usual to apply the term sensation to those perceptions only which are unaccompanied with the notion of their inhering in an outward object, as the pain arising from the incision of a sharp instrument is a sensation, which is not in the instrument. But in reality every thought, notion, idea, feeling, and perception, which distinguishes a sentient nature from unconscious existence, may be considered generally as sensation. Whereas perception, as used by some authors, (especially by Dr. Reid,) begs the 8question under debate; i.e. of the existence of objects or masses of external qualities already perceived. For under any illusion of the senses, a person would say, (as of sight, for instance,) "I thought there had been a bird in this room; until I perceived it was only a painting:" meaning that he made use of the whole knowledge relating to the subject, then in the mind, as an instrument, an inward eye, to correct the impressions at first received; and when the doctrine I propose becomes unfolded, the following is the conclusion to which I wish it may lead, viz. that the relations of various sensations generate conclusions, which become new sensations or perceptions, and which, as so many inward objects of sense, afford an evidence of the existence of the exterior objects to which they refer, equal to the evidence there is for any existing sensation whatever, in the mere consciousness of its presence. Mr. Hume uses the word perception in the sense I do that of sensation, i.e. for 9any consciousness whatever. But on account of the ambiguity to which that word is exposed, I prefer the latter term. However, when I occasionally use the word "perception," I use it in the sense of a "consciousness of sensation," a sensation taken notice of by the mind, and this is the sense in which Mr. Locke defines the word.19
2. Having said thus much for the sake of clearness, I proceed to state the question proposed, with some slight variation of expression, thus: Whence pg 35is it, that many of the sensations with which we are acquainted are considered as objects continuous in their existence, outward from, and independent of our own, when it is obvious, they are still upon the same footing as those are allowed to be, which are considered as interrupted, inward, and dependent beings; being all of them equally perceptions, or feelings of a mind, which when not perceiving, or feeling, cannot take notice of any existence whatever?
103. I answer that we do not conceive our sensations so to exist, but by habit associate them with the notion of some sort of corresponding continuous existences, and that we gain the knowledge that there must needs be some continuous (independent) existences, beings that are not sensations, by the means of reasoning, which reasoning itself consists of other and superinduced sensations, arising from the comparison of the relations, of simple sensations among themselves, thus testifying the existence of the external objects it represents, as much as the experience of simple sensations, (of colour, sound, &c.) testifies the existence of their respective internal objects; and that, although we be only conscious of our sensations, yet our whole combined sensations include in their relations the necessity, that there should be, and the proof that there are, other existences than the mere sensations themselves.
11In order to discover what these relations20 are, whence this result is deduced, let us inquire,
12First, by what means it is we acquire the notion of continuous existences, in opposition to the interrupted sensations, by which they appear to the mind?
Secondly, examine the foundations, for considering such objects external to, instead of a part of, or included in the perceiving mind.
pg 36Thirdly, further consider, whence the notion originates, that such objects are entirely independent of our own existence; although we can only know them by our sensations, which themselves depend upon our existence?
In the consideration of these three branches of the question, I shall take notice, how far the method nature takes to generate the notions of independent existence, proves it, and cursorily observe on the errors of Mr. Hume and Bishop Berkeley on these points, &c.
5 Part 4, sec. 2 [Treatise 1.4.2].
13 But this part of the subject will be more fully entered upon in a separate treatise [Essay 1, EPEU 195–238], where it is intended to introduce some extracts from Berkeley's "Principles of Human Knowledge," [i.e., Principles] and to apply the ideas here suggested as an answer to them.
17 In the beginning of his argument against Mr. Hume in his Inquiry of the Human Mind [Inquiry 6.1].
20 In dreams and madness the mind is not in a state to perceive and examine these relations; for, first, there is no remembrance of the place the percipient is in; therefore, the relation of place in regard to all those vivacious images which are moving in the fancy is wanting, which, did it exist, would show they were merely parcels of sensible qualities, independent of the action of the senses on external objects, and thus render the mind conscious it was in a delirium; a very peculiar state of mind no doubt, but one which experience proves may take place, and which at once renders futile that notion of Hume and Berkeley, that the reality of things consists only in the superior vivacity of their impressions.
Secondly, the mind is not in a fit state to perceive, that these masses of sensible qualities are not such as can return upon the sense when called for; and so are wanting in that proof of continuous existence.
Thirdly, the mind is not in a state to combine with these observations, the knowledge that these masses of sensible qualities cannot owe their existence to those methods of formation which in nature determine objects, independent of each man's sense in particular, and therefore, wholly different beings from the creatures of one man's fancy in particular, the result of a lively, or disordered circulation of the blood. This view of the subject will be further pursued in the discussion of this essay [EPEU 66–67/87–91].