You may call it taxation of power. Say, I do not really like a business environment where you (realistically) either have to become a big shark or go bust. I do not wish to take everything it takes to get sharky. The problem is to restrict or impede the power of sharks to take over my little business. One way is to make laws and rules; other way is to tax their power - let them roam, but impede their freedom with a taxing compensation. As wealth correlates with power in this world, and wealth is easily measurable, we come close to an interesting justification of taxing wealth (as a first approximation).