Mill distinguishes higher and lower pleasures in his essay on "Utilitarianism." Presumably higher pleasures are generally more intellectual pleasures and lower pleasures are more sensual pleasures. Mill's utilitarianism is an ethics that says the highest good is what produces the most pleasure. Bentham before him hadn't made this distinction and his ultilitarianism had been criticized as an "ethics of swine." Clearly, it seems, to maximize pleasures you should just seek the most and best of food, drink, sleep, sex, etc. But Mill comes along and responds that you should instead there are higher pleasures. So, reading a good book, seeing a good play or other edifying pleasures would be far superior and would supersede food, drink, sleep, sex etc.
The question is, are the type of pleasures he designates higher pleasures really more pleasurable? They seem to be the types of things that a well educated Victorian gentleman would valorize. Most philosophers (with rare exceptions like Aristippus and the Cyrenaic school, who valorized bodily pleasures) would agree. But I don't think most people would agree. Is Mill right?
To be fair to Mill lets try to compare apples to apples, and compare the most pleasurable intellectual pleasures with the most pleasurable physical pleasures, and try to see what we would prefer. The most pleasurable physical pleasure I think is clear: sex. And of course, we should imagine here good sex, with someone that you very much want to have sex with. The most pleasurable intellectual pleasure is not so clear. I think it would be curiosity. And I think the best example of that is a book that you simply can't put down. So, to discern whether intellectual pleasures are really higher try to think of being in the middle of a wonderfully engaging book that you simply can't put down (neither to eat or sleep) until you're done. At this point, the man or woman of desire requests that you put the book down and have sex right now. Do you a) keep reading and defer the sex for an hour (we'll assume, to make things equal, that the person is willing to wait an hour) or b) have sex and defer reading for an hour? Many would put the book down simply because it can wait whereas the other is a real person with feelings, but for the sake of this thought experiment, to keep things equal, we should imagine that the person is infinitely patient and won't feel slighted. Try to give both sides a fair shake. And try to think of the aftermath, of the pleasures after the fact from the one and the other If you'd choose the book, then maybe Mill is on to something. But if you choose the sex, maybe Mill's attempt to dodge the criticism that utilitarianism is nothing but swine morality is groundless.
Postscript. What would happen if I said the best physical pleasure is a sustained mind-blowing, cosmic, out-of-body Tantric orgasm? Is there any intellectual pleasures as good as that? Or is that an example of an intellectual pleasure?