A new perspective on philosophical debates Truthmaking A new perspective on philosophical debates

Plan Introduce the idea of a truthmaker. Introduce some of the key questions about truthmaking. Present an example of a different presentation of an old problem (the problem of universals).

Introduction to truthmaking

Truthmaking and truthmakers Consider the standard truth schema. The proposition that p is true if and only if p. This familiar schema has a hidden asymmetry. The proposition that p is true because of p. Not: P is a fact because the proposition that p is true. We might say: p makes the proposition true.

Truthmaking and truthmakers Truthmaking: a relation between a proposition and what grounds/explains/accounts for its truth. Truthmaker: an entity which makes a proposition true.

proposition Grass is green truthmaking relation truthmaking relation truthmaker

Why truthmakers? Some philosophers argue that truthmakers are required to ground the asymmetry of the truth schema. Asymmetry Argument (G. Rodriguez-Pereyra): It seems right that truth is grounded in reality, but that reality is not grounded in truth. Grounding is a relation. Relations need relata. So truths – true propositions – must be related to some additional entity – a truthmaker of some kind.

Key questions about truthmaking

Key questions What is the truthmaking relation like? Is the truthmaking relation necessitating? Does a truthmaker necessitate the truth of a proposition, or is it a contingent matter? Do we need some entities – truthmakers – to do the truthmaking? What kinds of things are truthmakers? Do they involve properties? Does every true proposition have a truthmaker?

What is the truthmaking relation like? A truthmaker principle: (TM) If p is true, then there exists an entity α such that α makes true p. What kind of relation does a truthmaker have to its truths? What is the relation between α and p like?

What is the truthmaking relation like? Is it a causal relation? (TMC) If p is true, then there exists an entity α such that α causes p to be true. Typically, we don’t think of propositions as standing in causal relations. What about mathematical truths etc.? Plausibly, the number 3 doesn’t bear causal relations to anything, and so can’t cause the proposition that 3 is prime to be true.

What is the truthmaking relation like? Is it a logical relation like entailment? (TME) If p is true, then there exists an entity α such that α entails that p. But entailment is a relation that holds between propositions (or sets of propositions). And α isn’t (always) a proposition (or set of them). Move from α, to the proposition that α exists: (TME*) If p is true, then there exists at least one entity α such that the proposition that α exists entails the proposition that p. But what makes it true that α exists? Presumably just α.

What is the truthmaking relation like? Perhaps the truthmaking relation is sui generis. But we can describe some features of it. The truth-making relation is cross-categorial. It relates different kinds of entity (propositions to something else). Some philosophers claim that the truthmaking relation is necessary.

Is the truthmaking relation necessitating? Truthmaker necessitarianism: the view that a truthmaker necessitates the truth of the proposition made true. If α is a truthmaker for p, then, necessarily, if α exists then it is true that p.

Truthmaking and the problem of universals

The problem of universals The problem of universals is an old problem. Sometimes it is also put in terms of the “one over many.” It can be difficult to get clear on what exactly the problem is, and what the constraints are on giving an answer. Here is one way that I introduce the problem to my students:

The problem of universals Some things seem to be the same in certain respects. E.g. What can explain what these different things all have in common? It is natural to say: they all have the same property (or quality, or feature), yellowness or being yellow. So a metaphysical theory of properties might then try to say more about this thing yellowness.

The problem of univerals and truthmaking The language of truthmaking can give us a different, perhaps clearer, way to introduce this kind of difficult, abstract problem. E.g. “It is true that the banana and the duck are both yellow. What makes this true?” “It is true that the duck is yellow. What makes this true?” “What are the truthmakers for similarity/difference propositions?” What are the truthmakers for propositions ascribing qualities to things?

The problem of univerals and truthmaking The theory of truthmaking can also guide the kinds of answers we give to those questions.

Key terms Sentence: a linguistic entity, made up of words. E.g. “The rose is red”. Proposition (Fregean) : a representation of a state of affairs / the meaning of a sentence. An abstract entity made up of representational constituents, such as concepts. E.g. <the rose is red>. State of affairs: a combination of worldly entities, particulars and universals, which can obtain or not obtain. E.g. the rose’s being red. Fact: obtaining state of affairs. Universal: qualitative entity which can be located in different places at the same time. E.g. redness. Particular: individual entity which has a unique location in space and time. E.g. Obama.

The problem of universals and truthmaking What makes contingent truths, such as <the rose is red>, true? Not the rose. It might have been a different colour. But TMN requires that a truthmaker necessitate its truth. Not the universal redness. It might not have been instantiated by the rose. But TMN requires that a truthmaker necessitate its truth. Proposal: The fact of the rose’s being red makes true <the rose is red>.

Facts as truthmakers Armstrong’s truthmaker argument Suppose that <α is red> is true. What makes it true? It can’t be α – α is a particular considered apart from its properties. It can’t be the pair of α and the universal F – the pair might have existed without α being F. (TMN) The obvious candidate is the fact that is composed of α and F: α’s being F.

Facts as truthmakers The truthmaker argument is supposed to start from the plausible assumption that simple propositions such as “The rose is red” are true, and take us to the conclusion that facts exist. It relies on the assumptions that true propositions have truthmakers, and that truthmaking is necessitating. Given that facts are complexes of particulars and universals, a commitment to the existence of facts brings along with it a commitment to the existence of universals. Hence, the truth of these simple propositions is supposed to commit us to the existence of universals.

Facts as Truthmakers There are, of course, alternative views on what the truthmakers of these propositions are. For example, Gonzalo Rodriguez-Pereyra argues that the proposition that, e.g., the apple and the rose are both red, is made true just by the particular things. The apple and the rose are the truthmakers for truths about their resemblances – no further metaphysical machinery is required. (A version of resemblance nominalism). So, one way to rethink the debate between different answers to the problem of universals is in terms of truthmakers for an important class of propositions. We can gain new insight into these different answers by understanding them in terms of the assumptions or claims they make about truthmaking.

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