Abstract
Haig and Borsboom advocate for psychological science to adopt a correspondence theory of truth. However, their argument requires a hidden premise that only correspondence theories of truth bring the benefits that they ascribe to correspondence. This premise is not plausible and their argument therefore does not support their recommendation. Additionally, considerations extraneous to Haig and Borsboom’s argument speak in favor of considering alternative theories of truth.
Keywords
Haig and Borsboom (2012) offered a useful exploration of the correspondence theories of truth as such theories relate to four different levels of claims commonly made in psychological research: procedural, data, phenomenal, and causal. They contrasted a correspondence theory of truth with various alternatives such as pragmatism, coherence, and postmodernism. (I will focus on the first two because I did not fully understand their characterization of the third.) Haig and Borsboom argued for a cosmopolitan approach to correspondence in which claims at different levels correspond to different truth-makers. They made four central claims for correspondence theories of truth: (a) correspondence theories allow one to explain the difference between fraud and scientific disagreement; (b) correspondence theories allow one to distinguish unproblematic from problematic claims based on the complexity of the implied truth-makers; (c) correspondence theories allow one to explain actions taken to refute a theoretical claim; and (d) correspondence theories allow one to outline a hierarchy of truth-makers to which different types of claims correspond. Haig and Borsboom concluded on the basis of this that correspondence theories of truth outperform alternative theories of truth: We have briefly suggested that the correspondence theory is much more useful than any of its competitors in distinguishing between fraud and falsity, in explaining how scientists gather refuting material, and in outlining the hierarchical and complex structure of facts presumed in high-level causal theories. (p. 287)
In the above, I have spoken of correspondence theories of truth in the plural form because there is more than one. Haig and Borsboom generally adopt a level of abstraction that glosses over the differences between correspondence theories of truth. For the most part, I will follow their lead in this respect.
My goal in this comment is to question a step in their argument to the above conclusion. I understand Haig and Borsboom’s argument as having the following schematic form.
A correspondence theory of truth defines truth in terms of a dyadic correspondence relation (C) holding between a claim (p) and a truth-maker (m): pCm.
Alternative theories of truth define truth in some other way than in terms of correspondence.
The concept of correspondence holds many advantages.
Therefore, correspondence theories of truth are preferable to alternatives.
I will not question the characterization of various theories of truth in premises 1 and 2. Further, I will not quibble with any of the advantages that they claim for a correspondence theory of truth with regard to premise 3. I will instead focus on the invalidity of the step from the three premises to the conclusion 4.
In order to make the conclusion follow from the premises, one requires at least one further hidden premise.
HP. Theories of truth that do not define truth in terms of correspondence do not have access to the advantages that come with the concept of correspondence.
Haig and Borsboom seem to take something like premise HP for granted throughout their exposition. My goal in this comment is to argue that nothing like premise HP is plausible. Alternative approaches to truth need not and generally do not deny correspondence (Künne, 2003, section 5.3.3). They differ from correspondence theories in that they do not take correspondences as definitive of truth. Nonetheless, it is entirely open to alternative theories to take correspondence as a property of true claims (or other truth bearers). Without premise HP, conclusion 4 fails to follow from the remaining premises.
To bring home the force of this argument, imagine that a coherence theorist presented the following argument: (1') Coherence theories define truth in terms of coherence. (2') Alternative theories define truth in other ways. (3') Coherence holds many advantages. Therefore (4') coherence theories of truth are preferable to alternative theories. Faced with this argument, a correspondence theorist would presumably claim that his or her preferred correspondence theory brings with it the benefits of coherence despite not defining truth in terms of coherence. However, the situation is entirely parallel for a coherence theorist, or an advocate of some other approach, to claim that his or her preferred theory of truth brings with it the benefits of correspondence despite not defining truth in terms of correspondence.
In the remainder of this comment, I shall first flesh out the idea that alternative theories of truth can allow for or entail correspondence without making it a criterion for truth. I shall then close by offering some reasons that one might prefer an alternative account of truth.
Correspondence without a correspondence theory of truth
How might correspondence without a correspondence theory of truth work? Let T stand for the touchstone for truth according to some non-correspondence theory of truth such that, according to the theory, p is true if and only if Tp. Further suppose that, according to this theory, if Tp then pCm. That is, if a proposition meets the criterion for truth according to this theory, then the proposition corresponds to its truth-maker in the appropriate way. Note, for purposes of the last section, that the conditional does not hold in the other direction: pCm is compatible with the failure of Tp. For a pragmatist theory of truth, T might involve successful future verification. For a consensus theory of truth, T might involve agreement at the end of inquiry. For a coherence theory of truth, T might involve coherence with a somehow optimized set of beliefs. In any case, the touchstone for truth is coextensive with truth. Any proposition identified as true by this touchstone also has the property of correspondence.
The hidden premise (HP) does not hold for any such theory. Theories of this type do not define truth in terms of correspondence. However, they do predicate correspondence of propositions that they categorize as true. As a result, such theories have access to all the benefits of correspondence cataloged by Haig and Borsboom (2012; namely a–d above).
Reasons for looking beyond correspondence theories of truth
I shall briefly consider three reasons that looking beyond correspondence theories may hold some attraction: the intelligibility of correspondence, accounting for logical truths, and the distinction between forthright and misleading truths.
The intelligibility of correspondence
Whatever intuitive attraction the idea of correspondence may hold, the goal of cashing it out in a clear and intelligible form remains elusive. Haig and Borsboom appear to favor some form, or forms, of fact correspondence as a means of cashing out the idea of correspondence. One might take this in one of at least two different ways. The first option is to take this at face value and understand true statements as corresponding to abstract entities called facts. One difficulty with this approach is infinite regress: If the fact that 52 participants completed the study makes the claim that 52 participants completed the study true, what makes it a fact that 52 participants completed the study? If a fact is a true proposition, what makes the proposition true that makes the claim true? Similarly, if facts are abstract entities, in what sense do they exist in a form to which true claims might correspond? If facts are mental entities, then claims nobody has thought about cannot hold true, yet it is not clear where facts fit into the material world either.
The second option is to understand facts as events. In this case, the event of the 52nd participant completing the study made the claim true. However, this view runs into trouble with certain types of claims that seem as if they ought to be understood as true. For example, if I state that the 52nd score in my data set is the score of the 52nd participant in the study, I make an identity claim. It is not clear that any particular event or collocation of events makes an identity claim true (Künne, 2003). Likewise, it remains unclear what specific event makes it true that no 53rd participant completed the study or that King Albert II did not participate in the study, although these claims seem clearly to hold true (Lewis, 1986). The explanation of truth in terms of correspondence to facts, construed either way, remains a promissory note yet to be cashed out. That may make advocacy premature.
Logical truths
Haig and Borsboom argued that correspondence truth applies to all true claims, only the specific notion of correspondence varies from one domain to another. However, correspondence theories have trouble with logical truths (Levine, 1996). Psychologists routinely rely on logical truths to critique theoretical claims. It is far more common to critique a theory on the basis of some unnoticed consequence or presupposition than on the basis of one announced in the statement of the theory. Logical truths link such criticism to the theory. Yet, logical truths do not appear to correspond to anything in particular. If they do, it is not clear how different logical truths correspond to different things. For example, If A then (A or B) differs in meaning from If (A and B) then A. It is hard for a correspondence theory of truth to distinguish the truth-makers of these two logical truths. Similar comments apply to general mathematical truths relied on by researchers to transform raw observations into testable statistical models. Haig and Borsboom acknowledge similar issues for mathematical and moral truths, but do not offer a correspondence account of their truth.
Misleading truths
A theory of truth differs from a theory of justification, but the two are not entirely independent. A theory of truth sets the framework within which a theory of justification must operate. A worry over correspondence theories of truth is that they restrict truth to a binary relationship between the proposition and its truth-maker and that they construe the truth-maker as independent of cognition. This framework encourages theories of justification that are similarly restricted in scope. Correspondence theories encourage the idea that one can justify a truth claim in isolation, focusing only on the proposition and its truth-maker, without engaging in dialog with others. Nonetheless, such dialog has value in the identification of presuppositions and critical evaluation of how one frames a truth claim.
As a consequence, correspondence theories are at a disadvantage with respect to distinguishing forthright truths from misleading truths. By a misleading truth I mean a claim that meets the correspondence criterion but that is framed in a way that misleads by begging a policy question, suggesting an incorrect presupposition, or otherwise encouraging some misunderstanding. As an example, imagine a hypothetical educational testing system that systematically excludes low-income students from advanced educational opportunities required for social mobility because low-income schools fail to provide preparation comparable to high-income schools. Claims that the testing system validly identifies students who are more likely to succeed constitute misleading truths in this hypothetical situation. They hold true according to their own internal logic, but they beg the policy question of whether admitting students based on their probability of success offers the optimal policy in this situation. As a second example, claims that treatment and control groups differ in outcomes might constitute misleading truths if they overlook the fact that only a small proportion of patients in the experimental group benefit from treatment, or that the benefits are uniformly too small to matter for all patients.
If psychological science is to offer a reliable beacon for policy decisions, then psychological science needs to be able to distinguish forthright truths from misleading truths. Correspondence theories of truth seem ill equipped to facilitate such distinctions. Theories of truth that look beyond narrow correspondence to a broader context offer a framework for justification that is more sensitive to such issues. This provides some further motivation for psychology as a discipline to look beyond correspondence theories of truth.
Conclusion
I congratulate Haig and Borsboom on a thoughtful and timely article with which I find much to agree. However, I question the hidden premise in their argument that one must define truth in terms of correspondence in order for a theory of truth to share the advantages of correspondence. Absent this premise, their argument does not support the conclusion that psychology should adopt a correspondence theory of truth. I see a number of reasons that psychologists might instead wish to pursue alternative theories of truth that account for correspondence without taking it as definitive of truth.
Footnotes
Acknowledgements
I would like to thank Anru Lee for helpful comments on an earlier version of this comment.
Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.