Maybe fundamentally different is too strong a claim, and it’s not really central. The main point is that even if we had absolute cardinal scales for pleasure and pain separately, it wasn’t clear to me how you could possibly combine these scales. However, based on the answers, if you start from preferences and assume a single scale for these, and then ignore things that don’t matter, you could get a common scale. This makes sense to me.
Maybe fundamentally different is too strong a claim, and it’s not really central. The main point is that even if we had absolute cardinal scales for pleasure and pain separately, it wasn’t clear to me how you could possibly combine these scales. However, based on the answers, if you start from preferences and assume a single scale for these, and then ignore things that don’t matter, you could get a common scale. This makes sense to me.