 Beginning with The Problems of Philosophy in 1912, Russell turned repeatedly to the problem of matter. As has been described by Omar Nasim (2008), Russell was stepping into an ongoing discussion of the relation of sense data to matter that was being carried on by T.P. Nunn (1910), Samuel Alexander (1910), G.F. Stout (1914), and G.E. Moore (1914), among others. The participants of this “Edwardian controversy”, as Nasim terms it, shared a belief that direct objects of perception, with their sensory qualities, were nonetheless extra-mental. The concept of matter, then, was the result of a loosely described social or psychological “construction”, going beyond what was directly perceived. A project shared by the participants in the controversy was the search for a refutation of George Berkeley’s idealism, which would show how the existence and real nature of matter can be discovered. In The Problems of Philosophy (Russell 1912) Russell argues that the belief in the existence of matter is a well supported hypothesis that explains our experiences. Matter is known only indirectly, “by description”, as the cause, whatever it may be, of our sense data, which we directly know by “by acquaintance”. This is an example of the sort of hypothesis that Russell contrasts with construction in the famous passage about “theft” and “honest toil”. Russell saw an analogy between the case of simply hypothesizing the existence of numbers with certain properties, those described by axioms, and hypothesizing the existence of matter.