| This is the cause of many mistakes and sophisms in philosophy; as will naturally be imagined, and as it would be easy to show, if there was occasion. |
| Of the three relations above-mentioned that of resemblance is the most fertile source of error; and indeed there are few mistakes in reasoning, which do not borrow largely from that origin. |
| Resembling ideas are not only related together, but the actions of the mind, which we employ in considering them, are so little different, that we are not able to distinguish them. |
| This last circumstance is of great consequence, and we may in general observe, that wherever the actions of the mind in forming any two ideas are the same or resembling, we are very apt to confound these ideas, and take the one for the other. |
| Of this we shall see many instances in the progress of this treatise. |
| But though resemblance be the relation, which most readily produces a mistake in ideas, yet the others of causation and contiguity may also concur in the same influence. |
| We might produce the figures of poets and orators, as sufficient proofs of this, were it as usual, as it is reasonable, in metaphysical subjects to draw our arguments from that quarter. |
| But lest metaphysicians should esteem this below their dignity, I shall borrow a proof from an observation, which may be made on most of their own discourses, viz. |
| that it is usual for men to use words for ideas, and to talk instead of thinking in their reasonings. |
| We use words for ideas, because they are commonly so closely connected that the mind easily mistakes them. |
| And this likewise is the reason, why we substitute the idea of a distance, which is not considered either as visible or tangible, in the room of extension, which is nothing but a composition of visible or tangible points disposed in a certain order. |
| In causing this mistake there concur both the relations of causation and resemblance. |
| As the first species of distance is found to be convertible into the second, it is in this respect a kind of cause; and the similarity of their manner of affecting the senses, and diminishing every quality, forms the relation of resemblance. |
| After this chain of reasoning and explication of my principles, I am now prepared to answer all the objections that have been offered, whether derived from metaphysics or mechanics. |
| The frequent disputes concerning a vacuum, or extension without matter prove not the reality of the idea, upon which the dispute turns; there being nothing more common, than to see men deceive themselves in this particular; especially when by means of any close relation, there is another idea presented, which may be the occasion of their mistake. |
| We may make almost the same answer to the second objection, derived from the conjunction of the ideas of rest and annihilation. |
| When every thing is annihilated in the chamber, and the walls continue immoveable, the chamber must be conceived much in the same manner as at present, when the air that fills it, is not an object of the senses. |
| This annihilation leaves to the eye, that fictitious distance, which is discovered by the different parts of the organ, that are affected, and by the degrees of light and shade;--and to the feeling, that which consists in a sensation of motion in the hand, or other member of the body. |
| In vain should we.search any farther. |
| On whichever side we turn this subject, we shall find that these are the only impressions such an object can produce after the supposed annihilation; and it has already been remarked, that impressions can give rise to no ideas, but to such as resemble them. |
| Since a body interposed betwixt two others may be supposed to be annihilated, without producing any change upon such as lie on each hand of it, it is easily conceived, how it may be created anew, and yet produce as little alteration. |