By Catarina Dutilh Novaes
A bit over five years ago I wrote a blog post on Hugo Mercier and Dan Sperber’s then-recently published paper on their argumentative theory of reasoning. At that point I was about to start a research project on deductive reasoning, having as my main hypothesis the idea that deductive reasoning is best understood from a dialogical – and thus, argumentative – perspective, and so naturally the argumentative theory of reasoning was something to pay attention to. Yesterday was officially the very last day of my research project, and fittingly, earlier this week we convened for the very last (official) reading group session of the project to discuss a very recent paper by Andy Norman (CMU), forthcoming in Biology and Philosophy: ,‘Why we reason: intention-alignment and the genesis of human rationality’. The paper presents a broadly evolutionary account of human reasoning faculties, which takes on board much of Mercier & Sperber's (M&S) argumentative theory, but modifying it in important respects. Here is the abstract:
Why do humans reason? Many animals draw inferences, but reasoning—the tendency to produce and respond to reason-giving performances—is biologically unusual, and demands evolutionary explanation. Mercier and Sperber (Behav Brain Sci 34:57–111, 2011) advance our understanding of reason’s adaptive function with their argumentative theory of reason (ATR). On this account, the “function of reason is argumentative… to devise and evaluate arguments intended to persuade.” ATR, they argue, helps to explain several well-known cognitive biases. In this paper, I develop a neighboring hypothesis called the intention alignment model (IAM) and contrast it with ATR. I conjecture that reasoning evolved primarily because it helped social hominins more readily and fully align their intentions. We use reasons to advance various proximal ends, but in the main, we do it to overwrite the beliefs and desires of others: to get others to think like us. Reason afforded our ancestors a powerful way to build and maintain the shared outlooks necessary for a highly collaborative existence. Yes, we sometimes argue so as to gain argumentative advantage over others, or otherwise advantage ourselves at the expense of those we argue with, but more often, we reason in ways that are mutually advantageous. In fact, there are excellent reasons for thinking this must be so. IAM, I suggest, neatly explains the available evidence, while also providing a more coherent account of reason’s origins.