Appendix 39.

(952) [Reid on judgment and sensation]

It seems to me that here Reid is not perfectly coherent with himself, or at least that his explanation is somewhat obscure. On the one hand, he says that perception is of its nature totally different from sensation: perception is made by means of a natural judgment which affirms external bodies; sensation does not extend beyond the soul which feels itself modified. In other words, perception and sensation are evidently different powers. He seems to affirm this even more clearly where he speaks of perception as a mysterious faculty within the spirit, that is, something definitely different from sensation. On the other hand, he says that sense does not exist without judgment; the word 'sense' in everyday language, to which he appeals, always expresses an ability to judge. It was philosophers who mistakenly divided these two things (sense and judgment) and made two faculties of them (Essays on the Powers of the Human Mind, etc., vol. 2, p. 176).

We see that Reid finds contradictions in philosophers but cannot determine the cause. According to him, they define sense as a power giving us ideas without judgment, and judgment as a power to compare the ideas given us by sense. Granted this, he says, philosophers are forced to define sense in the same way as they describe judgment (if ideas are to come from sense). As proof of this he takes an example from the second chapter of Locke's fourth book where Locke calls the eyes judges of colour and thus attributes the faculty of judgment to sense.

Although this observation is totally true, Reid, who notes the incoherence of philosophers, is unable to determine the cause.
His inability results from the failure of philosophers to distinguish carefully between the nature of sensation and that of intellection or idea. They failed to observe that ideas can be obtained only by means of a judgment, and that sensations are received in us without a judgment.
They saw on the one hand that 1. sense is not judgment, and on the other, 2. sensation and idea were more or less the same thing, although idea did not exist without judgment. This led them to describe sense as if it were a judgment, without their being aware of the contradiction between the conclusion and the distinction they had already made between the faculty of feeling and that of judgment.
Reid tried to remove the contradiction by suggesting that sense must not be defined as different from judgment but as a judgment itself. He appeals to common sense and thinks he has determined common opinion by investigating the use of words, which are depositaries of commonly held beliefs. He finds that the words 'sense' and 'feeling' are used to mean judgment, and therefore concludes that people in general consider judgment to be the same as feeling.
But these thoughts of Reid simply inform us that we are not safe from error when we say, 'I intend to follow common sense'. Common sense, like a book written by a very learned person, must be read with great attention and interpreted with great wisdom.

Indeed, if it were true that people in general confuse feeling with judgment, as Reid maintains, this must surely be a general error rather than a general truth. The reasons I have given to demonstrate the necessary distinction between sense and judgment cannot, it seems to me, leave any doubt about the distinction (cf. several places in volume 1, particularly 218 ss.). If the expression, 'The senses judge', is to be excused, it must be understood as a summary expression for 'Judgment follows sense'. In my opinion however, this manner of speaking is often misunderstood by people in general who have never analysed the operations of their own spirit nor distinguished the two very closely united operations of sense and of judgment accompanying sense. When they do reflect, they fail to see the distinction and fall into the error of judging the two things as one.

I have no difficulty in accepting other expressions such as 'This person has this feeling', 'I feel in this way', etc., I have no difficulty in accepting them as good and true when they are used to express actions pertaining to intelligence. There is in fact an intellectual sense which is the principle and source of every intellective action (cf. 553). As St. Augustine says, est enim sensus et mentis [The mind too is a sense] (Retract., bk. 1, c. 1). This intellectual sense however must not be confused with our bodily senses.