I praise Hugh Mellor for his important contributions to scientific realism and to empirical metaphysics and for his espousal of the notion of truthmakers, that in the world in virtue of which truths are true. These three doctrines, or perhaps directions of thought, interlock in a natural and powerful way. To many of us they seem to give a charter for progress in philosophy, however slow and struggling that progress may be.
Truth, I think, attaches fundamentally to propositions. We may then define realism about the truth of a particular true proposition as the contention that its truth is determined by something that lies outside that proposition. This is at least a plausible thesis for the vast majority of true propositions, and I take this plausibility to be the charter for truthmaking theory. In general, propositions that are true have this property of truth in virtue of some portion or portions of the world. (In some cases the word 'portion' must not be too narrowly construed.) It is these portions of the world that we truthmaker theorists call truthmakers.
I go on to make two rather strong claims. The first is Truthmaker Necessitarianism. The determining of a truth by a truthmaker is a necessitation, an absolute necessitation. Notice that we should not say that it is an entailment (as I have wrongly said in the past). Entailment can hold only between propositions, and generally at least the truthmaker for a truth will not be a proposition. The connection is cross-categorial. The simplest, if somewhat uninteresting, example of such a necessity holds between any truthmaker, T, and the truth
Notice that necessitarianism seems to require that we take truths as propositions rather than as beliefs, statements, and such. Truthmakers, entities in the world, can hardly necessitate beliefs and statements about these entities, generally at least. What are propositions, then? I think that they are the intentional objects of actual or possible beliefs, statements and so on. I hope to give a naturalist, empiricist and, to a degree, deflationary account of intentional objects. All this, however, must be left aside here.