McDowell’s Direct Realist Reply to Scepticism

McDowell’s claim that in veridical cases of perception objects are “immediately present to the mind” has earned him the title of direct realist. Direct realism is the thesis that what we perceive are not merely appearances (insert: sense data, veil or ideas or whatever else suits your fancy) but rather objects themselves.

Direct realism can be used against arguments for external world scepticism (EWS) of of the following form:

P1: Our EW beliefs are based on sense data beliefs
P2: Sense data beliefs cannot justify EW beliefs
EWS: Our EW beliefs are not justified

The direct realist resists EWS by rejecting P1. There are two senses in which the direct realist can maintain that our EW beliefs are not based on sense data beliefs. First, they can deny that there are such things as sense data beliefs. This is certainly true in McDowell’s case since his rejection of the highest common factor view, a fortiori, includes the eschewal of any such mediating beliefs. Second, if we interpret the locution ‘based on’ in a strong inferential sense, then a direct realist may insist that our EW beliefs are not inferred from any other beliefs at all but are rather immediately grasped by the perceiving subject.

However, the locution ‘based on’ need not be taken in this strong inferential sense. A sceptic may insist that there can be a weak sense of ‘based on’ that is non-inferential. For example, we may interpret the phrase ‘based on’ in causal terms. Putatively, it seems undeniable that our EW beliefs are causally based on appearances or sense impressions. According to an empirical-psychological account of vision, the act of seeing an object involves several complex physiological processes. Moreover, we never see objects themselves, but merely the light bundles reflected off an object. Thus, there are several causal intermediaries between our EW beliefs and the objects in the eternal world. Thus, our sceptical argument may be reformulated as follows:

P1*: Our EW beliefs are (causally) based on sensory appearances
P2*: Sensory appearances cannot justify EW beliefs
EWS: Our EW beliefs are not justified

Significantly, P1* does not assert that sensory appearances are the intentional object of our perceptual experience. For instance, by P1*’s lights we are free to view sensory appearances as the means rather than object of our perceptions. In other words, P1* merely asserts that sensory appearances form part of the causal chain linking our beliefs to the EW that gives rise to our beliefs. Thus, P1* can be construed along purely direct realist lines—to wit, we may hold P1* while simultaneously maintaining that objects themselves (and not some mental intermediary) are the intentional objects of our perceptions. Thus, even if we grant direct realism’s denial of an inferential intermediary, P1* still stands.

Unfortunately for the sceptic, this reply fails in the case of McDowellian direct realism. McDowell may gladly concede that the causal descriptions (with all its various intermediary steps) of empirical psychology are true. However, McDowell maintains that the empirical-psychological account is not only one available. In fact, McDowell draws on the Sellarsian idea of there being a sui generis “space of reasons” for precisely this reason. When McDowell describes perception as being direct, he is speaking in terms of the logical space of reasons, not in terms of the logical space in which the subject matter of empirical science falls. Things like photons or electrical impulses are  not of the right sort to act as a reason for one's beliefs. Trading on this ambiguity in the locution ‘based on’, McDowell may accept P1*, but point out that P1* cannot plausibly be combined with P2* in order to generate EWS.  P1* (explicitly) exploits the epistemically insignificant notion of being ‘causally’ based on, while P2* (implicitly) exploits the  epistemically significant notion of being ‘justificationally’ based on.  This equivocation in the explicit notion of "based on" in P1* and the implicit notion of "based on" in P2* prevents the inference from going through.

In sum, McDowellian direct realism is effective against sceptical arguments of a certain form. Specifically, sceptical arguments that ride on there being an inferential or causal intermediary between our EW beliefs and the objects we perceive are easily defeated by direct realist considerations. Of course,  arguments for EWS may take other forms as well.

Moore On Sense Data

One of the central questions in the philosophy of perception is: what are the objects of perception? One way to interpret the locution ‘objects of perception’ is in terms of what it is that we are immediately aware of in the act of perceiving. In the early 20th century the traditional answer to this question was ‘sense data’ (henceforth SD). Thus, Moore defines SD as that which we ‘directly apprehend’ in perception [p. 46 ff*]. A striking feature of Moore’s account of SD is that he appears to remain open to the possibility that SD are mind-independent [p. 31, 43-5]. For example, Moore opines that SD may continue to exist even when we do not perceive them [p. 31], in which case their existence would not be dependent on the mind of the perceiver. In this regard, Moore’s conception of SD differs slightly from that of most contemporary philosophers who view mind-dependence as a fundamental feature of SD (a fact which Moore [p. 40-3] himself acknowledges).

Moore points out that when we combine (1) the assumption that in perceptual experience we only directly apprehend SD, with (2) the standard view of SD as mind-dependent, we appear to quickly run into epistemological difficulty [p. 48]. The former claim makes SD the basis for our perceptual beliefs while the latter allows for the possibility that SD only exist in the mind of the perceiver without any corresponding physical objects. Together, they appear to invite scepticism regarding our belief in the existence of physical objects since said belief is based on something that is compatible with there being no physical object. Significantly, the above line of reasoning rests on the equating of mind-dependence with object-independence (and by ‘object-independence’ I mean the thesis that SD (can) exists independently of any corresponding physical object). However, it is conceivable that SD could be simultaneously mind-dependent and object-dependent (for example, we may conceive of SD as arising out of some type of interaction between the mind and object). Moore seems to conflate mind-dependence and object-independence [p. 48], though he does avoid making the inverse mistake of assuming that mind-independence equals object-dependence (more on the latter claim below).

At times Moore seems to lean toward the view that SD may actually be identical to the physical surfaces of objects, but at no point does he ever endorse this view. Such reluctance on the part of Moore seems warranted since identifying SD with the surfaces of objects falls prey to one of the challenges that led philosophers to posit SD in the first place—namely, the problem of hallucinations. Since in the case of hallucinations, unlike illusions, there is no object present at all, there is nothing for SD to adhere to. Thus, even if he were to concede that SD are mind-independent, if he is to account for hallucinations, Moore must maintain that SD are object-independent (as he does in fact do). Another question that Moore appears to remain neutral on is whether SD are physical or non-physical entities. If the former, then Moore seems forced to identify them with the surfaces of objects (a prospect we have already deemed unattractive). However, if he regards them as non-physical then Moore seems faced with the difficulties of explaining what exactly they are and how could they interact causally (if at all) with our sensory faculties. In sum, it remains unclear whether Moore regarded SD as mind-dependent or mind-independent, or physical or non-physical. But this much seems clear: whatever they are, SD must (by Moore’s lights) be object-independent [p. 50].

Question: Does Moore ever come to a final position on whether (1) are SD mind-independent or mind-dependent or (2) are SD physical or non-physical?

*All citations refer to the first chapter of Moore’s Some Main Problems of Philosophy.