T 2.2.12.1

BUT to pass from the passions of love and hatred, and from their mixtures and compositions, as they appear in man, to the same affections, as they display themselves in brutes; we may observe, not only that love and hatred are common to the whole sensitive creation, but likewise that their causes, as above-explain'd, are of so simple a nature, that they may easily be suppos'd to operate on mere animals. There is no force of reflection or penetration requir'd. Every thing is conducted by springs and principles, which are not peculiar to man, or any one species of animals. The conclusion from this is obvious in favour of the foregoing system.