knowledge, but are obliged after all to say knowledge of the good?

How ridiculous!

Yes, I said, that they should begin by reproaching us with our ignorance of the good, and then presume our knowledge of it — for the good they define to be knowledge of the good, just as if we understood them when they use the term ‘good’ — this is of course ridiculous.

Most true, he said.

And those who make pleasure their good are in equal perplexity; for they are compelled to admit that there are bad pleasures as well as good.

Certainly.

And therefore to acknowledge that bad and good are the same?

True.