P27: If we imagine a thing like us, toward which we have had no affect, to be affected with some affect, we are thereby affected with a like affect.

Dem.: The images of things are affections of the human Body whose ideas represent external bodies as present to us (by IIP17 S), i.e. (by IIP16), whose ideas involve the nature of our Body and at the same time the present nature of the external body. So if the nature of the external body is like the nature of our Body, then the idea of the external body we imagine will involve an affection of our Body like the affection of the external body. Consequently, if we imagine someone like us to be affected with some affect, this imagination will express an affection of our Body like this affect. And so, from the fact that we imagine a thing like us to be affected with an affect, we are affected with a like affect. But if we hate a thing like us, then (by P23) we shall be affected with an affect contrary to its affect, not like it, q.e.d.

Schol.: This imitation of the affects, when it is related to Sadness is called Pity (on which, see P22 S); but related to Desire it is called Emulation, which, therefore, is nothing but the Desire for a thing which is generated in us from the fact that we imagine others like us to have the same Desire.

Cor. 1: If we imagine that someone toward whom we have had no affect affects a thing like us with Joy, we shall be affected with Love toward him. On the other hand, if we imagine him to affect it with Sadness, we shall be affected with Hate toward him.

Dem.: This is demonstrated from P27 in the same way P22 is demonstrated from P21.

Cor. 2: We cannot hate a thing we pity from the fact that its suffering affects us with Sadness.

Dem.: For if we could hate it because of that, then (by P23) we would rejoice in its Sadness, which is contrary to the hypothesis.

Cor. 3: As far as we can, we strive to free a thing we pity from its suffering.

Dem.: Whatever affects with Sadness what we pity, affects us also with a like Sadness (by P27). And so (by P13) we shall strive to think of whatever can take away the thing’s existence, or destroy the thing, i.e. (by P9 S), we shall want to destroy it, or shall be determined to destroy it. And so we strive to free the thing we pity from its suffering, q.e.d.

Schol.: This will, or appetite to do good, born of our pity for the thing on which we wish to confer a benefit, is called Benevolence, which is therefore nothing but a Desire born of pity. As for Love and Hate toward him who has done well or ill to a thing we imagine to be like us, see P22 S.