In the previous chapter I explained the connection between Peirce's cosmology and his theory of inquiry. I argued that he arrives at his views about the origins and evolution of the universe by thinking through the implications of the hypothesis that laws are real, in light of the principles of his theory of inquiry. Proceeding in this way, Peirce concludes that not only does each law in the universe require explanation but so too does the emergence of lawfulness out of ‘nullity’. On the theory he develops, laws result from the working out of a tendency to generalize events that happen by chance. For him, then, ‘tychism’ – his term for the view that chance is operative in the order of things – forms a central part of the hypothesis that laws are real.

As Peirce sees it, tychism is contrary to nominalism. The nominalist holds that the objective content of knowledge can be reduced to claims about individuals. To Peirce's way of thinking, this limits the scope of knowledge to claims about what exists and leads the nominalist to deny ontological significance to claims about what is possible (i.e. what might be), probable (i.e. what is likely to be) or necessary (i.e. what must be). The nominalist denies, in particular, that statistical generalizations in science – lawlike claims involving probabilities – represent real statistical principles operating in the world.