Keynesian economics is founded on the idea of economics being quasi-random (specifically, aggregate demand). However, Keynesian economics are also demand-side. These combined portray the economy as essentially random, moving up and down with no discernable order or rationality. Thus, Keynes said that supply creates demand.

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However, this is not correct. People do tend to behave rationally and in accordance with their own prerogatives and available information, they will not simply buy whatever stocks the shelves just because it is available. Rather, businesses develop in response to the need for a product/service if there is available capital and sufficient profit motivation to satisfy said need.