**1. Introduction**

Knowledge is commonly seen as consisting of two forms. The knowledge how to do something, such as riding a bike, and the knowledge that something is the case, such as that Reykjavík is the capital of Iceland.<sup>1</sup> Ryle [1,2] set an enduring and influential modern debate in motion by discussing the relation between the two forms. According to intellectualism, which Ryle opposes, knowledge how is a form of knowledge that. According to anti-intellectualism on the other hand, which Ryle supports, knowledge how involves abilities and dispositions, and is thereby not a form of knowledge that (see, e.g., [1–3]):

Cleverness at fighting is exhibited in the giving and parrying of blows, not in the acceptance or rejection of propositions about blows ... [n]or does the surgeon's skill function in his tongue uttering medical truths but only in his hands making the correct movements. [2] (p. 48).

Stanley and Williamson [3–5] offers a thought-provoking intellectualist account of knowledge, where they—against Ryle—argue that knowing-how is a form of propositional knowing-that. We will focus on Stanley's [3] formulation, where he presents an intellectualist account arguing that facts are true propositions and that knowledge of how to do things is knowledge of facts:

[K]nowing how to do something is the same as knowing a fact. It follows that learning how to do something is learning a fact. For example, when you learned how to swim, what happened

<sup>1</sup> The distinction is standard in the literature and we will use it throughout the article. However, there are, of course, other conceptualizations of knowledge including, for example, knowledge by *acquaintance*, as well as knowing *which*, *who*, *what*, *what* it is like etc.

is that you learned some facts about swimming. Knowledge of these facts is what gave you knowledge of how to swim. Something similar occurred with every other activity that you now know how to do, such as riding a bicycle or cooking a meal. You know how to perform activities solely in virtue of your knowledge of facts about those activities. [3] (p. vii).

As Schwartz and Drayson [6] point out, it is crucial to make one's own stance in the intellectualist/anti-intellectualist debate clear since a lot of confusion arguably stems from theoreticians talking past each other depending on whether their focus is on semantics or science. In philosophy, numerous different approaches for investigating knowledge have been discussed and promoted, however, the most common focus has been on the *concept* knowledge, and Stanley's argumen<sup>t</sup> centers on a semantic approach. This said, he explicitly discusses cognitive scientific evidence and claims that it supports his position [3,7]. Therefore, this approach is motivated to assess Stanley's claim using a naturalistic approach where the *natural phenomenon* knowledge, such as science presents it, is seen as being of primary interest.<sup>2</sup> Our approach is thus cooperative, and complementarily evolutionary, naturalistic in the sense that we consider it essential to take empirical evidence and scientific theories into account—trumping intuitions—when such input is available in order to find a plausible account of knowledge. All philosophical questions are then legitimate, although their answer will need to be compatible with scientific input [8–14].

There have been a number of naturalistic attacks on Stanley's position (see, e.g., [15–17]), ye<sup>t</sup> while we largely agree with most of these arguments, we want to add a pluralistic perspective that highlights consideration of the nature of slips and basic activities as well as the scientific multi-level coherence for the case against intellectualism.

In short, we claim that the intellectualist position of knowledge how is untenable in light of relevant scientific theorizing and evidence. In defense of our view, we put forth and defend the following two theses: (1) knowledge how and knowledge that should be seen as two distinct forms of knowledge, and (2) intellectualism is neuroscientifically and psychologically implausible.
