It was an application of Occam's razor. Dark energy arises automatically in the Standard Model. That is, you don't put it in by hand -- it emerges no matter wha

It was an application of Occam's razor. Dark energy arises automatically in the Standard Model. That is, you don't put it in by hand -- it emerges no matter what you do. In fact, we often get too much of it; this is the cosmological constant problem.