Online research in philosophy

The aim of this paper is to provide an overview of various forms of alethic pluralism. Along the way we will draw a number of distinctions that, hopefully, will be useful in mapping the pluralist landscape. Finally, we will argue that a commitment to alethic disjunctivism, a certain brand of pluralism, might be difficult to avoid for adherents of the other pluralist views to be discussed. We will proceed as follows: Section 1 introduces alethic monism and alethic pluralism. Section 2 presents a distinction between strong and moderate versions of monism and pluralism, understood as theses about the existence of truth properties. Section 3 introduces four pluralist positions: strong alethic pluralism, alethic disjunctivism, second-order functionalism and manifestation functionalism. These positions are classified using the basic framework from Section 2, and a further distinction between pure and mixed versions of pluralism is drawn. Interestingly, alethic disjunctivism and the two kinds of functionalism—i.e. three out of four positions— have a mixed character. They incorporate a monist thesis. The only pure form of pluralism is strong alethic pluralism. Section 4 adds another distinction to the stock: one-level and two-level views. Each of the mixed positions operates with two levels, locating certain “alethically potent”—or grounding—properties at a lower level and others at a higher level. We briefly discuss the nature of grounding. In Section 5, we answer a question about mixed, two-level views, viz. whether they are as much monist as pluralist in nature, or more. They are not. Section 6 is devoted to the task of arguing that the strong pluralist, the second-order functionalist, and the manifestation functionalist will find it hard to deny a commitment to alethic disjunctivism.

The aim of this paper is to provide an overview of various forms of alethic pluralism. Along the way we will draw a number of distinctions that, hopefully, will be useful in mapping the pluralist landscape. Finally, we will argue that a commitment to alethic disjunctivism, a certain brand of pluralism, might be difficult to avoid for adherents of the other pluralist views to be discussed. We will proceed as follows: Section 1 introduces alethic monism and alethic pluralism. Section 2 presents a distinction between strong and moderate versions of monism and pluralism, understood as theses about the existence of truth properties. Section 3 introduces four pluralist positions: strong alethic pluralism, alethic disjunctivism, second-order functionalism and manifestation functionalism. These positions are classified using the basic framework from Section 2, and a further distinction between pure and mixed versions of pluralism is drawn. Interestingly, alethic disjunctivism and the two kinds of functionalism—i.e. three out of four positions— have a mixed character. They incorporate a monist thesis. The only pure form of pluralism is strong alethic pluralism. Section 4 adds another distinction to the stock: one-level and two-level views. Each of the mixed positions operates with two levels, locating certain “alethically potent”—or grounding—properties at a lower level and others at a higher level. We briefly discuss the nature of grounding. In Section 5, we answer a question about mixed, two-level views, viz. whether they are as much monist as pluralist in nature, or more. They are not. Section 6 is devoted to the task of arguing that the strong pluralist, the second-order functionalist, and the manifestation functionalist will find it hard to deny a commitment to alethic disjunctivism.

Here is a well-known thought about truth: Truth consists in correspondence with reality. A sentence is true just in case what it says corresponds with how the world is. Theories of truth that incorporate this thought are naturally regarded as robust or “heavyweight”. Truth is to be understood in a realist fashion. The world decides what is true and what is not. A recent incarnation of the correspondence view is found in truth-maker theories, whose adherents maintain that truths are true in virtue of there being something – a truth-maker – in the world that makes them so.2.

Here is a well-known thought about truth: Truth consists in correspondence with reality. A sentence is true just in case what it says corresponds with how the world is. Theories of truth that incorporate this thought are naturally regarded as robust or “heavyweight”. Truth is to be understood in a realist fashion. The world decides what is true and what is not. A recent incarnation of the correspondence view is found in truth-maker theories, whose adherents maintain that truths are true in virtue of there being something – a truth-maker – in the world that makes them so.2.

A difficulty for alethic pluralism has been the idea that semantic evaluation of conjunctions whose conjuncts come from discourses with distinct truth properties requires a third notion of truth which applies to both of the original discourses. But this line of reasoning does not entail that there exists a single generic truth property that applies to all statements and all discourses, unless it is supplemented with additional, controversial, premises. So the problem of mixed conjunctions, while highlighting other aspects of alethic pluralism worth investigating further, does not constitute an effective objection to it.

The problem of mixed conjunctions, due to Tappolet (2000), threatens to undermine alethic pluralism by showing that it cannot account for the truth of conjunctions in which the conjuncts spring from different domains of discourse. In this paper I argue, firstly, that the problem is not just a problem for alethic pluralism and, secondly, that the problem can be solved.

Consider truth predicates. Minimalist analyses of truth predicates may involve commitment to some of the following claims: (i) truth “predicates” are not genuine predicates -- either because the truth “predicate” disappears under paraphrase or translation into deep structure, or because the truth “predicate” is shown to have a non-predicative function by performative or expressivist analysis, or because truth “predicates” must be traded in for predicates of the form “true-in-L”; (ii) truth predicates express ineligible, non-natural, gerrymandered properties; (iii) truth predicates express metaphysically lightweight properties; (iv) truth predicates have thin conceptual roles; (v) truth predicates express properties with no hidden essence; (vi) truth predicates express properties which have no causal or explanatory role in canonical formulations of fundamental theories.

Mixed inferences are a problem for those who want to combine truth-assessability and antirealism with respect to allegedly nondescriptive sentences: the classical account of validity has apparently to be given up. J.C. Beall's response is that validity can be defined as the conservation of designated valued (Beall 2000). I argue that since it presupposes a truth predicate that can be applied to all sentences, this suggestion is not helpful. I also consider problems arising from mixed conjunctions and discuss the deeper worry that the distinction between truth which does and truth which does not entail realism is inferentially irrelevant.

Alethic pluralists argue truth is a metaphysically robust higher-order property that is multiply realized by a set of diverse and domain-specific subvening alethic properties. The higher-order truth property legitimizes mixed inferences and accounts for a univocal truth predicate. Absent of this higher-order property, pluralists lack an account of the validity of mixed inferences and an adequate semantics for the truth predicate and thereby appear forced to abandon the central tenets of alethic pluralism. I argue the use of many-valued logics to support pluralism fails to address the pluralist’s metaphysical problem regarding mixed inferences and mixed truth functional connectives. The high degree of heterogeneity of the alethic realizers (unlike the realizers for pain) challenges the plausibility of a single higher-order functional property. A functional property with such a heterogeneous base cannot be projectable at a theoretically significant level. The problem with mixed inferences and truth functions is but one symptom of the deeper projectability problem.

In reply to Geach's objection against expressivism, some have claimed that there is a plurality of truth predicates. I raise a difficulty for this claim: valid inferences can involve sentences assessable by any truth predicate, corresponding to 'lightweight' truth as well as to 'heavyweight' truth. To account for this, some unique truth predicate must apply to all sentences that can appear in inferences. Mixed inferences remind us of a central platitude about truth: truth is what is preserved in valid inferences. The question is why we should postulate truth predicates that do not satisfy this platitude.