 What is the motivation for adopting a theory of truth-makers, whether maximalist or optimalist? Following Sider, it has become customary to describe the “whole point” of adopting a theory of truth-makers thus: to “Catch the cheaters” who don’t believe in truth-makers (Sider 2001: 40–1; see also Merricks 2007: 2–3). But this is a bit like saying that the point of a benefit system is to catch out benefit frauds. It’s only if there is some antecedent point in favour of truth-makers that there can be anything wrong with leaving them out. Nonetheless, it is possible that we can come to appreciate the need for truth-makers by appreciating what is lacking in theories that neglect them. This is how C.B. Martin and Armstrong came to recognise the necessity for admitting truth-makers (Armstrong 1989b: 8–11, 2004: 1–3). Consider phenomenalism: the view that the physical world is a construction out of sense-impressions. One obstacle for this view is the need to make sense in sense-impression terms of true claims we make about the unobserved world. Martin noticed that the phenomenalist could only appeal to brute, ungrounded counterfactuals about possible experience to do so. But counterfactuals do not float free in a void. They must be responsive to an underlying reality, the reality that makes them true. For Martin this was the phenomenalists’ fatal error: their inability to supply credible truth-makers for truths about unobserved objects. The same error afflicted Ryle’s behaviourism with its brute counterfactuals about non-existent behaviour and Prior’s presentism according to which there is nothing outside the present and so there is nothing for past-tensed and future-tensed truths to be held responsible to. We come to appreciate the need for truth-makers as the common need these different theories fail to fulfil.