To forestall an objection: I think investing with a goal of improving the world as opposed to maximizing income, is basically the same as giving, so that comes into the category of how to spend, not how much money to allocate for it. If you were investing rather than giving, and had income from it, you’d simply allocate it back into the category.
This thread is interesting, but off-topic. There is lots of useful discussion on the most effective ways to give, but that wasn’t my question.
To forestall an objection: I think investing with a goal of improving the world as opposed to maximizing income, is basically the same as giving, so that comes into the category of how to spend, not how much money to allocate for it. If you were investing rather than giving, and had income from it, you’d simply allocate it back into the category.