1. What is the function of reasoning?

On the one hand, it seems that the capacity to reason is a cognitive superpower which enabled Homo sapiens to gain an immense amount of knowledge that set our species far apart from the rest of the animal kingdom. On the other hand, there is robust evidence that people display seemingly irrational reasoning biases. How could this “flawed superpower” have evolved? What, if anything, is the adaptive function of reasoning?

A number of influential researchers in philosophy, psychology, and cognitive science have proposed that the human capacity to reason evolved for individuals to manipulate others through persuasion and self-justification. It is widely supposed that this view of reason renders confirmation bias (or “myside bias”) a feature rather than a bug, since such a bias helps the reasoner build a case in favor of their beliefs. In “The Evidence is Not on My Side: Reason, Evolution, and Bias” (completed draft) I show that what allows the view to explain myside bias is not the function of reason it posits, but rather the auxiliary hypothesis that in achieving this function it was cost-effective to offload to interlocutors the task of formulating counterarguments. I show that this explanatory strategy can be mimicked under rival views of the function of reason. For example, myside bias may have evolved to enable a division of argumentative labor that allowed groups to reach the truth efficiently, or to enable lone individuals to efficiently test their own beliefs by bringing to mind the grounds for those beliefs.

In “Cracking the Enigma: Cultural Knowledge, Social Learning, and Private Reason” (completed draft) I propose that the capacity to reason evolved for individuals to generate true beliefs for the purpose of solving novel problems in the environment. Drawing on ethnographic studies of hunter-gatherer societies, I argue that the fitness of individuals in the relevant ancestral environments was enhanced by reasoning taking as input rule-like cultural knowledge transmitted through stories. 

2. What is the nature of reasoning?

Reasoning can be about any topic whatsoever; it can be inductive or deductive; it can be good or bad. These general, formal, and normative characteristics of reasoning are commonly explained by the hypothesis that reasoning essentially involves following rules concerning the premises from which one reasons. Furthermore, reasoning is something that we do intentionally. This personal and active character of reasoning is commonly explained by further supposing that there is an important distinction between rule-following and mere rule-conformity, with rule-following essentially involving intentional mental states that represent the relevant rule and play a causal role in the relevant process.

It has been argued that putting these two independently plausible hypotheses together leads to a vicious regress. The problem is generated by supposing that all rule-following involves grasping what the rule states, forming a belief that the antecedent is satisfied, and drawing the conclusion that the act specified by the consequent is required – thus it seems that all rule-following involves reasoning, in addition to all reasoning involving rule-following. In “Reasoning, Rules, and Representation” (Naturalizing Logico-Mathematical Knowledge, 2018), co-authored with Richard Samuels, we show that the regress argument is unsound. We posit a level of primitive processing mechanisms that take rule-representations as inputs. The primitive processes they subserve are rule-guided in the thin sense that a rule-representation is causally implicated in the process. However, primitive processes are not rule-guided in the sense that they involve further rule-guided or inferential sub-processes. If non-primitive processes ultimately decompose into primitive ones, no regress is generated.

3. Does reasoning tend to be biased?

Various notions of psychological bias (e.g. “cognitive bias”, “reasoning bias”, “implicit bias”) have gained traction in the public sphere. How are the biases to be understood? In my research I have concentrated on one bias in particular. Early research by Peter Wason on hypothesis testing suggested that people tend to select and interpret evidence in ways that often unintentionally favor the hypothesis at hand. Recently it has been argued that this general form of “confirmation bias” holds only when what is at stake is not an arbitrary hypothesis but rather the views of the reasoner and is thus better described as “myside bias”.

In “Wason Confirmed: Why Confirmation Bias Is Not Myside Bias in Disguise” (draft completed) I defend Wason’s original claim that when people test a hypothesis that takes the form of a conditional statement, rather than search for falsifying cases, they tend to unintentionally search for instances of the conditional which, if discovered, confirm the hypothesis. It is in this sense that a bias towards confirming evidence exists. I further argue that contrary to widespread opinion, there is no good evidence that people tend to unintentionally search for evidence that favors their beliefs. However, I conclude by proposing a novel experimental paradigm that is capable of providing evidence for myside bias.