The implications of dual rationality for the evaluative question

It is generally assumed by dual-process theorists that System 1 and System 2 differ in many respects. But then one immediate challenge for dual-process theory concerns the relationships between the two systems. How do they interact with one another? In particular, how can System 2 override cognitive mechanisms belonging to System 1 when they are triggered by the same input?

The question of how the two systems interact with one another is the Achilles’ heel of any dual process theory. For example, Evans and Over give us no detailed or satisfactory account of that. This seems to be a missing detail which Evans himself recognizes. As he writes, “an important challenge is to develop models to show how such two distinct systems interact in one brain and to consider specifically how the conflict and competition

between the two systems might be resolved in the control of behaviour” (Evans 2003: 458).

In particular, what is needed is an account of how the two systems interact together. This account may allow the corresponding dual rationality theory to be used to assess human reasoning. On the one hand, given the consequentialist understanding of rationality it should be easy to understand when System 2 overrides System 1, that is, when doing so helps us to reach our goals in the current context. On the other hand, however, as is noted by Over (2004: 11), “it can be difficult, and sometimes impossible, in practice to decide when to override”. Both System 1 and System 2 are the product of evolution, but only System 2 permits us to pursue goals that are not directly linked to reproductive success.

While System 1 is governed by domain-specific and automatic cognitive mechanisms, System 2 permits to figure out how to attain personal goals. It is clear that not all people have reproductive success as one of their goals in System 2, although that goal belongs to them as a goal of System 1 (Over 2004: 10-11). As a result, the two systems are aimed at different and sometimes competing domains of goals. This shows that we cannot characterize rationality simply in terms of inclusive fitness or adaptiveness, or simply replace the classical standards of rationality by evolutionary or ecological ones.

6. Concluding remarks

A good way to ground normative claims about rationality is by appealing to the outcomes that good reasoning should lead to. Consider two of the most important implications that the adoption of a consequentialist approach has for the rationality question. First of all, a consequentialist conception assumes that the norms of rationality are both psychologically dependent and robustly context-dependent. Indeed, contrary to the idea that norms of rationality are universal, consequentialism implies that what good reasoning is may vary

across contexts. Normative standards must be relativized to goals and environments: a reasoning strategy that leads reliably to a good outcome in a given context is, therefore, a normatively appropriate way of achieving that goal in that context, but not necessarily in other contexts. Secondly, according to the consequentialist approach, the normative and the descriptive question (see Chapter 1, Section 1.1) are inextricably interrelated because only a psychological theory of reasoning can identify a collection of reasoning strategies out of which to select the most effective strategies in a given context.

Within this theoretical framework, heuristics, such as those characterized by Kahneman and Tversky, can be justified consequentially because they help us reach two goals: an outcome which the reasoner values and the sparing of time and energy. Inasmuch as successful outcomes are characterized in terms of their conduciveness to inclusive fitness, then it follows that reasoning performances are rational to the extent to which they contribute to increase reproduction and inclusive fitness. As seen above, this standpoint has been supported by two different but related traditions: evolutionary psychology and ecological rationality. Although their proponents have correctly re-evaluated the rationality of heuristic processes, their analyses are based on a misinterpretation of human rationality.

As is pointed out by Stanovich and West (2003: 172), “what these theorists have missed (or failed to sufficiently emphasize) is that definitions of rationality must coincide with the level of the entity whose optimization is at issue”. That calls for a distinction between adaptive rationality and “personal” rationality and the goals which are connected to them.

Indeed, although evolutionary psychologists acknowledge that the conditions in the environment of evolutionary adaptation do not always match those of our current world, they do not take into consideration the consequences of not clearly distinguishing between goals linked, directly or indirectly, to inclusive fitness and personal goals.

To conclude, consider again the expression “organism’s adaptive goals” which is so often used by both evolutionary psychologists and Gerd Gigerenzer (see Chapter 3, Section 4.2). As is noted by Stanovich and West (2003: 206-207), it is possible to attribute two different meanings to this expression. On the one hand, as evolutionary psychologists hold, the word “adaptive” suggests that we are specifically talking about evolutionary/adaptive goals. On the other hand, we can focus on the word “organism” and view the concepts of rationality proposed by evolutionary psychologists and Gigerenzer as closer to that of consequentialist personal rationality. If “adaptive” goals are taken to refer to the environment in which a reasoner is situated, reasoning performances ought to be assessed in terms of their success in achieving the goals people aim at, given the constraints imposed by their current environment (and not by referring to the environment of evolutionary adaptation). In the next chapter, I will focus on this second interpretation of the expression

“organism’s adaptive goals”. In particular, I will explore a consequentialist approach to rationality assessment that is not strictly dependent on the characterization of rationality in terms of inclusive fitness or evolutionary adaptiveness.