Part of it is clarifying the claim. Is it "some positive effects" meaning some subset of all the effects being positive or "overall positive effect" meaning th

Part of it is clarifying the claim. Is it "some positive effects" meaning some subset of all the effects being positive or "overall positive effect" meaning the sum of all the negative and positive effects is positive? The first one is pretty simple, you just need to find one positive effect. The second is much more difficult and requires making judgements of the relative size of good and bad effects which is much more subjective, and I could see someone's view of subjective waits making it impossible for this to ever be true. But both views still require deciding if something is positive, which isn't exactly a scientific question. It is a bit like asking if evolution has positive effects. From a purely scientific view, is life or increased complexity of life a positive?