An argument I frequently hear (and generally buy into) against impact investing is that fungibility of investment money leads to unethical actors taking the extra wins created by impact investing. Hence, one should optimize for capital gains in 'investment' buckets and optimize for philanthropy in the 'doing good' bucket.
I'm concerned that this argument could then be applied to the money in my philanthropic bucket.
That is, does reducing my wealth by giving shift more capital gains onto non-altruistic actors? Put another way, in the long run under market economies, does philanthropy reduce the power of altruistic actors and increase the power of non-altruistic actors? If not, why?
You are correct. Through the safety net funded by altruists, egoists can afford lower taxes and receive greater benefits. As a result, egoists get stronger and altruists get weaker. That is, those who benefit themselves through charitable giving or don't give at all will become richer and stronger, while those who give to benefit society will become poorer and weaker.
Even if you think that the effects caused by your charity will grow exponentially, this not only still holds true but even more so. For these effects clearly manifest as a transfer from the altruistic to the selfish. Therefore, if this transfer grows exponentially, then the selfish will become more profitable and the altruistic will become more impaired.
This, in short, is part of the evidence for the argument of socialists in the broad sense that improving society requires collective action, not individual charity. Even social democrats advocate improving the social safety net through taxes and state benefits, not through tax-deductible subsidized charitable giving.
Tell me more! Why do you think this is true? Do you have anything to read further on the topic?