... a mixed cause could still be better than a pure benefit case. However, this will not be true on average ...
That's the question, what is the base rate of the options you are likely to notice. If visible causes come in equivalent pairs, one with harm in it and another without, all other traits similar, that would be true. Similarly if pure benefit causes tend to be stronger. But it could be the case that best pure benefit causes have less positive impact than best mixed benefit causes.
... since I take disagreements pretty seriously I think it is normally false in practice. In other words there is actual harm and actual benefit in almost every real case.
How does your taking disagreements seriously (what do you mean by that?) inform the question of whether most real (or just contentious?) causes involve actual harm as well as benefit? (Do you mean to characterize your use of the term "disagreement", which causes you point to as involving disagreement? For example, global warming could be said to involve no disagreement that's to be taken seriously.)
Yes, it could be the case that the best pure benefit causes have less positive impact than the best mixed benefit causes. But I have no special reason to believe this is the case. If benefit of the doubt is going to go to one side without argument, I would put it on the side of pure benefit causes, since they don't have the additional negative factor.
By taking disagreements seriously, I mean that I think that if someone disagrees with me, there is a good chance that there is something right about what he is saying, and especially in issues of policy (i.e. ...
The article is here.
The book is by William MacAskill, founder of 80000 Hours and Giving What We Can. Excerpt: