Most non-economists tend to think that economists know what they are talking about when they use specific terms like income, profit, capital, market equilibrium, and so on. This is not the case. What, then, follows from the well-documented fact that the representative economist has no idea of what profit is? Quite simple: if the core concept of profit is false then the whole economic theory/model is false. This holds for the Walrasian, the Keynesian, the Marxian, and the Austrian approach.