Elqayam & Evans (E&E) drive a wedge between Bayesianism and instrumental rationality that most decision scientists will not recognize. Their analogy from linguistics to judgment and decision making is inapt. Normative models remain extremely useful in the progressive research programs of the judgment and decision making field.

The Origin of Concepts sets out an impressive defense of the view that children construct entirely new systems of concepts. We offer here two questions about this theory. First, why doesn't the bootstrapping process provide a pattern for translating between the old and new systems, contradicting their claimed incommensurability? Second, can the bootstrapping process properly distinguish meaning change from belief change?

Rational models vary in their goals and sources of justification. While the assumptions of some are grounded in the environment, those of others – which I label probabilistic models – are induced and so require more traditional sources of justification, such as generalizability to dissimilar tasks and making novel predictions. Their contribution to scientific understanding will remain uncertain until standards of evidence are clarified.

Self-deception is a powerful but overapplied theory. It is adaptive only when a deception-detecting audience is in the loop, not when an inaccurate representation is invoked as an internal motivator. First, an inaccurate representation cannot be equated with self-deception, which entails two representations, one inaccurate and the other accurate. Second, any motivational advantages are best achieved with an adjustment to the decision rule on when to act, not with a systematic error in an internal representation.

Carey's superb discussion of the origin of concepts is extended into the field of cognitive ethology. I also suggest that agency may be a default mechanism, often leading to over-attribution. The problem therefore becomes one of specifying the conditions in which agency is not attributed. The significance of attentional/focusing abilities on conceptual development is also emphasized.

Deliberative democracy is one of the best designs that could facilitate good public policy decision making and bring about epistemic good based on Mercier and Sperber's (M&S's) theory of reasoning. However, three conditions are necessary: (1) an ethic of individual epistemic humility, (2) a pragmatic deflationist definition of truth, and (3) a microscopic framing power analysis during group reasoning.

We distinguish between literal and metaphorical applications of Bayesian models. When intended literally, an isomorphism exists between the elements of representation assumed by the rational analysis and the mechanism that implements the computation. Thus, observation of the implementation can externally validate assumptions underlying the rational analysis. In other applications, no such isomorphism exists, so it is not clear how the assumptions that allow a Bayesian model to fit data can be independently validated.

I suggest psychologists would more profitably study a totally different area of human reasoning than is discussed in the target article – the inductive reasoning people use in their everyday life that matters in consequential real-life decision making, rather than the deductive reasoning that psychologists have studied meticulously but that has relatively less ecological relevance to people's lives.

Having defended the usefulness of our definition of reasoning, we stress that reasoning is not only for convincing but also for evaluating arguments, and that as such it has an epistemic function. We defend the evidence supporting the theory against several challenges: People are good informal arguers, they reason better in groups, and they have a confirmation bias. Finally, we consider possible extensions, first in terms of process-level theories of reasoning, and second in the effects of reasoning outside the lab.

The breadth-first search adopted by Bayesian researchers to map out the conceptual space and identify what the framework can do is beneficial for science and reflective of its collaborative and incremental nature. Theoretical pluralism among researchers facilitates refinement of models within various levels of analysis, which ultimately enables effective cross-talk between different levels of analysis.

Social desirability can be conceived as a proxy for self-deception, as it involves a positive attribution side and a denial side. People with mental disorders have lower scores on measures of social desirability, which could depend on cognitive load caused by symptoms. This suggests that self-deception is an active strategy and not merely a faulty cognitive process.

Are infants' initial object representations innately specified? We examine the development of perceptual completion in infants by highlighting two issues. First, perceptual completion is supported by neural mechanisms that rely on experience with the environment. Second, we present behavioral and modeling data that demonstrate how perceptual completion can emerge as a consequence of changes in visual attention and oculomotor skill.

We applaud many aspects of Elqayam & Evans' (E&E's) call for a descriptivist research programme in studying reasoning. Nevertheless, we contend that normative benchmarks are vital for understanding individual differences in performance. We argue that the presence of normative responses to particular problems by certain individuals should inspire researchers to look for converging evidence for analytic processing that may have a normative basis.

A central claim of Jones & Love's (J&L's) article is that Bayesian Fundamentalism is empirically unconstrained. Unless constraints are placed on prior beliefs, likelihood, and utility functions, all behaviour – it is proposed – is consistent with Bayesian rationality. Although such claims are commonplace, their basis is rarely justified. We fill this gap by sketching a proof, and we discuss possible solutions that would make Bayesian approaches empirically interesting.

We argue that approaches adhering to normative systems can be as fruitful as those by descriptive systems. In measuring people's perception of randomness, discrepancies between human behavior and normative models could have resulted from unknown properties of the models, and it does not necessarily lead to the conclusion that people are irrational or that the normative system has to be abandoned.

Carey's book describes many cases in which children develop new concepts with expressive power that could not be constructed out of their input. How does she side-step Fodor's paradox of radical concept nativism? I suggest that it is by rejecting the tacit assumption that psychology can only explain concept acquisition when it occurs by rational inference or other transitions that are explicable-by-content.

Deflationists about self-deception understand self-deception as the outcome of biased information processing, but in doing so, they lose the normative distinction between self-deception and wishful thinking. Von Hippel & Trivers (VH&T) advocate a deflationist approach, but they also want preserve the purposive character of self-deception. A biologically realistic analysis of deception can eliminate the contradiction implicit in their position.

In advocating Bayesian Enlightenment as a solution to Bayesian Fundamentalism, Jones & Love (J&L) rule out a broader critique of rationalist approaches to cognition. However, Bayesian Fundamentalism is merely one example of the more general phenomenon of Rationalist Fundamentalism: the tendency to characterize human judgments as rational and optimal in a post hoc manner, after the empirical data are already known.