At its simplest, ethical hedonism is the claim that all and only pleasure has positive importance and all and only pain or displeasure has negative importance. This importance is to be understood non-instrumentally, that is, independently of the importance of anything that pleasure or displeasure might cause or prevent.
In addition, I wonder whether having the following equalities in mind would clarify discussions about ethics:
- "X is morally good/positive" = "X is intrinsically good/positive" = "X ought to be" = "X increases goodness/utility" = "X improves wellbeing (conscious experiences)".
- "X is morally bad/negative" = "X is intrinsically bad/negative" = "X ought not to be" = "X decreases goodness/utility" = "X worsens wellbeing (conscious experiences)".
- "Pleasure" = "positive utility/wellbeing" = "good/positive conscious experiences".
- "Pain" = "negative utility/wellbeing" = "bad/negative conscious experience".
In the 1st 2 points, the 3rd and 4th italicised equal signs only apply to utilitarianism and henodism, respectively. However, even if only implicitly/subconsciously, I think people tend to mean "X improves wellbeing according to my best heuristics" when they say "X is morally good". As Sharon Rawlette mentioned in episode 138 of The 80,000 Hours Podcast:
I actually think that if we didn’t ever experience pleasure [positive conscious experiences] or pain [negative conscious experiences], or any of these positive or negative qualitative states, that we wouldn’t actually have the concept of intrinsic goodness that we do in fact have and that we do use when we’re making moral decisions.
At a fundamental level, I guess differences between ethical theories are only related to the heuristics used to assess the value of actions. For example, the focus in deontology is on following certain rules, and in consequentialism on the consequences of the actions. However, all theories are about assessing conscious experiences, as by definition that is what can be perceived.
If this is so, at least in informal discussions, if not in the literature, it might be useful to have the above equalities in mind, and shift the focus of discussions towards assessing empirical evidence, including our conscious experiences.