The following article is one of many published in a series on “escape.” You can find out more about the project and articles similar to this one here.
Philosophical skepticism is a theory that, from an argument about the neutrality of experiences of perception, concludes that knowledge and, further, reasonable belief is impossible, particularly about the external world. The deeply unsettling nature of this conclusion has prompted countless attempts to refute it, to escape the skeptical anxiety induced by the argument’s force. One such attempted escape is externalism, which defines knowledge in such a way as to allow the possibility that we do in fact know things about our world. However, externalism provides nothing more than a cleverly crafted technical loophole. It fails to address that which is truly concerning about the skeptic’s claim and, therefore, to provide an escape from the anxiety skepticism prompts.
In order to demonstrate the inadequacy of externalism as an escape from skeptical anxiety, let us first consider the structure of the skeptical argument. The skeptic first states that all our supposed knowledge of the world results from experiences of perception. The skeptic then posits that experiences are always neutral between numerous possibilities: the same perception could result from multiple states of affairs. For example, if one sees what looks like a window overlooking a meadow, that perception could be explained by the presence of an actual window, or by the presence of a glass pane placed over a convincing photograph of a meadow. Or, to use a more unsettling skeptical scenario, one’s experiences of the external world could be explained equally well by the actual presence of the external world one perceives or by a simulation being applied to one’s brain in a lab. The perception would be neutral in either case, meaning that the experience of seeing a window or of being in the external world is neutral between both cases, and, in fact, between many other possible cases. The argument continues that if an experience is neutral in this way, one cannot know that the explanatory state of affairs they see is the right one based on the experience (from seeing the window, one can’t know that it’s not a photograph, and from experiencing the world, one can’t know that it’s not a simulation). If one can’t know that the alternate state of affairs isn’t the case, the argument continues, one can’t know, or have reason to believe, that the supposed state of affairs is the case: the evidence used to conclude this supposed case supports the alternate case equally well. Therefore, one cannot possibly definitively know or reasonably believe anything about the actual state of the external world.
Externalism introduces a definition of knowledge designed to combat skepticism. Here is one version of an externalist argument: one knows that something is the case, the externalist claims, if (a) one believes that something is the case and if (b) that belief exists because the thing actually is the case. Externalism therefore claims that knowledge of the external world is possible: if our perceptions actually are explained by what we think they are explained by (the existence of the real world), then we do know all the things that we think we know. This account of knowledge does indeed seem to capture some intuitive truth: it seems convincing to say that if, to use the earlier example, one believes that a window exists, and if that belief is caused by there actually being a window (as opposed to by there being a simulation), then one does indeed know that the window exists. The account is tempting in that it includes the causal connection between reality and belief that, intuitively, seems required for knowledge. This picture, however, becomes complicated when, instead of attempting, from an outside perspective to determine the validity of the spectator’s supposed knowledge, one considers the situation of the actual person seeing the “window”. This person lacks the epistemically privileged position that we have been taking in the course of this debate, and has no way to determine whether this causal connection exists.
As this person is no more sure of the validity of his beliefs than he was before, externalism is an entirely unsatisfactory response to the skeptical argument. One concerned that he does not know whether the world he perceives exists or he is experiencing a simulation would in no way be comforted by the claim that as long as the world he perceives does exist, then he knows that it does. Given that his initial concern was whether or not the world he perceives exists in fact, he would, after being presented with this externalist reassurance, immediately repeat a rephrased version of his original question: instead of asking “does the world I perceive exist?” he would ask “do I know that the world I perceive exists?” The externalist’s attempt to define knowledge solely in terms of true belief, without requiring awareness that one’s belief is true, has clearly done nothing to assuage the skeptical anxiety. Knowledge, as defined by the externalist, becomes trivial, as what one troubled by skepticism really cares about is knowledge that his beliefs are true. The technical, definitional maneuver upon which the externalist supposed answer to skepticism rests fails to address the question that those concerned by skepticism actually care about, making it a completely inadequate response.
In order to be genuinely satisfactory, a resolution of the skeptical argument would have to argue that we actually know that what we believe about the external world corresponds to reality (not that we could know this but may or may not). The externalist has therefore failed to escape the anxiety introduced by the skeptical argument and remains unsure of his convictions.