Doing good with other people's money has two basic flaws. In the first place, you never spend anybody else's money as carefully as you spend your own. So a large fraction of that money is inevitably wasted. In the second place, and equally important, you cannot do good with other people's money unless you first get the money away from them. So that force - sending a policeman to take the money from somebody's pocket - is fundamentally at the basis of the philosophy of the welfare state.