CHAP. IV.
THE SIX CLASSES OF INTELLECTUAL PLEASURES AND PAINS.
I have now dispatched the history and analysis of the sensations, motions, and ideas; and endeavoured to suit them, as well as I could, to the principles laid down in the first chapter. My next business is, to inquire particularly into the rise and gradual increase of the pleasures and pains of imagination, ambition, self-interest, sympathy, theopathy, and the moral sense; and to see how far these can be deduced, in the particular forms and degrees that are found to prevail, in fact, from the sensible pleasures and pains, by means of the general law of association. As to that of vibrations, it seems of little importance in this part of the work, whether it be adopted or not. If any other law can be made the foundation of association, or consistent with it, it may also be made consistent with the analysis of the intellectual pleasures and pains, which I shall here give. I do not think there is any other law that can; on the contrary, there seems to be so peculiar an aptness in the doctrine of vibrations, for explaining many of the phænomena of the passions, as almost excludes all others.
Now it will be a sufficient proof, that all the intellectual pleasures and pains are deducible ultimately from the sensible ones, if we can shew of each intellectual pleasure and pain in particular, that it takes its rise from other pleasures and pains, either sensible or intellectual. For thus none of the intellectual pleasures and pains can be original. But the sensible pleasures and pains are evidently originals. They are therefore the only ones, i.e. they are the common source from whence all the intellectual pleasures and pains are ultimately derived.
When I say, that the intellectual pleasures A and B are deducible from one another, I do not mean, that A receives back again from B that lustre which it had conferred upon it; for this would be to argue in a circle; but that whereas both A and B borrow from a variety of sources, as well as from each other, they may, and indeed must, transfer by association, part of the lustre borrowed from foreign sources upon each other.
