Our understanding of dual-process models of cognition may benefit from a consideration of language processing, as language comprehension involves fast and slow processes analogous to those used for reasoning. More specifically, De Neys's criticisms of the exclusivity assumption and the fast-to-slow switch mechanism are consistent with findings from the literature on the construction and revision of linguistic interpretations.

This commentary is sympathetic to De Neys's revision of dual-process theory but argues for a modification to his position on exclusivity and proposes a bold further revision, envisaging a dual-process theory 3.0, in which system 1 not only initiates system 2 thinking but generates and sustains it as well.

De Neys makes a compelling case that the sacrificial moral dilemmas do not elicit competing “fast and slow” processes. But are there even two processes? Or just two intuitions? There remains strong evidence, most notably from lesion studies, that sacrificial dilemmas engage distinct cognitive processes generating conflicting emotional and rational responses. The dual-process theory gets much right, but needs revision.

We consider an underdeveloped feature of De Neys's model. Decisions with multiple intuitions per option are neither trivial to explain nor rare. These decision scenarios are crucial for an assessment of the model's generalizability and adequacy. Besides monitoring absolute differences in intuition strength, the mind might add the strengths of intuitions per choice option, leading to competing and testable hypotheses.

A person who arrives at correct solutions via false premises is right and wrong simultaneously. Similarly, a person who generates “logical intuitions” through superficial heuristics can likewise be right and wrong at the same time. However, heuristics aren't guaranteed to deliver the logical solution, so the claim that system 1 can routinely produce the alleged system 2 response is unfounded.

De Neys offers a welcome departure from the dual-process accounts that have dominated theorizing about reasoning. However, we see little justification for retaining the distinction between intuition and deliberation. Instead, reasoning can be treated as a case of multiple-cue decision making. Reasoning phenomena can then be explained by decision-making models that supply the processing details missing from De Neys's framework.

This commentary identifies two problems concerning the switch mechanism: The model explains too few instances of switching, and the switching mechanism itself seems fallible. The improvements we suggest are to clarify the nature of the competing intuitions as the initial intuition and its negation or alternative ways to solve the problem, and to incorporate cognitive disfluency into the switching mechanism.

Why are only some occasions of system 1 to system 2 switching affectively loaded? This commentary not only draws attention to this neglected phenomenon, but also shows how research in philosophy and the social and cognitive sciences sheds light on it, doing so in ways that may help answer some of the open questions that De Neys's paper highlights.

We compare the predictions of two important proposals made by De Neys to findings in the anchoring effect literature. Evidence for an anchoring-and-adjustment heuristic supports his proposal that system 1 and system 2 are non-exclusive. The relationship between psychophysical noise and anchoring effects, however, challenges his proposal that epistemic uncertainty determines the involvement of system 2 corrective processes in judgment.

De Neys's incisive critique of empirical and theoretical research on the exclusivity feature underscores the depth of the challenge of explaining the interplay of fast and slow processes. We argue that a closer look at research on mindreading reveals abundant evidence for the exclusivity feature – as well as methodological and theoretical perspectives that could inform research on fast and slow thinking.

De Neys argues against assigning exclusive capacities to automatic versus controlled processes. The dual implicit process model provides a theoretical rationale for the exclusivity of automatic threat processing, and corresponding data provide empirical evidence of such exclusivity. De Neys's dismissal of exclusivity is premature and based on a limited sampling of psychological research.

By stipulating the existence of a system 1 and a system 2, dual-process theories raise questions about how these systems function. De Neys identifies several such questions for which no plausible answers have ever been offered. What makes the nature of systems 1 and 2 so difficult to ascertain? The answer is simple: The systems do not exist.

De Neys proposed a “switch” model to address what he argued to be lacuna in dual-process theory, in which he theorized about the processes that initiate and terminate analytic thinking. We will argue that the author neglected to acknowledge the abundant literature on metacognitive functions, specifically, the meta-reasoning framework developed by Ackerman and Thompson (2017), that addresses just those questions.

Computational-level models proposed in recent Bayesian cognitive science predict both the “biased” and correct responses on many tasks. So, rather than possessing two reasoning systems, people can generate both possible responses within a single system. Consequently, although an account of why people make one response rather than another is required, dual processes of reasoning may not be.

If we accept that societally, politically, and even culturally enlightenment face some serious challenges, can we use this rethinking of theories of reasoning to address them? The aim here is to make a case for building on the work presented by De Neys as an opportunity to advance an applied reasoning research programme.

Culture-as-situated cognition theory provides insight into the system 1 monitoring algorithm. Culture provides people with an organizing framework, facilitating predictions, focusing attention, and providing experiential signals of certainty and uncertainty as system 1 inputs. When culture-based signals convey that something is amiss, system 2 reasoning is triggered and engaged when resources allow; otherwise, system 1 reasoning dominates.

De Neys proposes that deliberation is triggered and sustained by uncertainty. I argue that there are cases where deliberation occurs with low uncertainty – such as when problems are excessively complicated and the reasoner decides against engaging in deliberation – and that there are likely multiple factors that lead to (or undermine) deliberation. Nonetheless, De Neys is correct to surface these issues.

De Neys makes some useful points regarding dual-process models, but his critique ignores highly relevant theories of judgment from the persuasion literature. These persuasion models predate and often circumvent many of the criticisms he makes of the dual-process approaches he covers. Furthermore, the persuasion models anticipated some of the correctives to dual-process models that he proposes.

We argue that the dual-system approach and, particularly, the default-interventionist framework favored by De Neys unnecessarily constrains process models, limiting their range of application. In turn, the accommodations De Neys makes for these constraints raise questions of parsimony and falsifiability. We conclude that the extent to which processes possess features of system 1 versus system 2 must be tested empirically.

The binary distinction De Neys questions has been put forward many times since the beginnings of psychology, in slightly different forms and under different names. It has proved enormously useful and has received detailed empirical support and careful modeling. At heart the distinction is that between knowledge in long-term memory and control processes in short-term memory.