John McDowell’s paper “Sellars and the Space of Reasons” (2018) provides a useful discussion of this concept. Unlike Brandom, who aims to complete Sellars’ break with empiricism, McDowell ultimately wants to defend “a non-traditional empiricism, uncontaminated by the Myth of the Given” (p. 1).

McDowell begins by quoting Sellars: “in characterizing an episode or a state as that of knowing, we are not giving an empirical description of that episode or state; we are placing it in the logical space of reasons, of justifying and being able to justify what one says” (ibid; emphasis added).

For Sellars, to speak of states of knowing is to talk about “epistemic facts”. A bit later, McDowell says that Sellars’ epistemic facts also include judgments and uses of concepts that might not be considered knowledge. Not only beliefs but also desires end up as a kind of epistemic facts. McDowell uses this to argue that the space of reasons is a version of the concept of knowledge as justified true belief. I want to resist this last claim.

McDowell points out that knowledge for Sellars has a normative character. Sellars also regards the foundationalist claim that epistemic facts can be explained entirely in terms of non-epistemic facts (physiology of perception and so on) as of a piece with the naturalistic fallacy in ethics.

McDowell cites Donald Davidson’s contrast between space-of-reasons intelligibility and the kind of regularity-based intelligibility that applies to a discipline like physics, but does not want to assume there is a single model for all non-space-of-reasons intelligibility.

He notes that Sellars contrasts placing something in the space of reasons with empirical description, but wants to weaken that distinction, allowing epistemic facts to be grounded in experience, and to be themselves subject to empirical description. “Epistemic facts are facts too” (p. 5). I prefer going the other direction, and saying empirical descriptions are judgments too.

The space of reasons is only occupied by speakers. Sellars is quoted saying, “all awareness of sorts, resemblances, facts, etc., in short all awareness of abstract entities — indeed, all awareness even of particulars — is a linguistic affair” (p. 7, emphasis in original). “And when Sellars connects being appropriately positioned in the space of reasons with being able to justify what one says, that is not just a matter of singling out a particularly striking instance of having a justified belief, as if that idea could apply equally well to beings that cannot give linguistic expression to what they know” (ibid).

“‘Inner’ episodes with conceptual content are to be understood on the model of overt performances in which people, for instance, say that things are thus and so” (p. 8). “What Sellars proposes is that the concept of, for instance, perceptual awareness that things are thus and so should be understood on the model of the concept of, for instance, saying that things are thus and so” (p. 10). All good so far.

To be in the space of reasons, “the subject would need to be able to step back from the fact that it is inclined in a certain direction by the circumstance. It would need to be able to raise the question whether it should be so inclined” (pp. 10-11, emphasis in original). But McDowell says — and I agree — that this is without prejudice as to whether there is still a kind of kinship between taking reasons as reasons, on the one hand, and the purposeful behaviors of animals, on the other.

McDowell acknowledges that the idea that epistemic facts can only be justified by other epistemic facts is easy to apply to inferential knowledge, but rather harder to apply to the “observational knowledge” that he claims should also be included in the space of reasons. For McDowell, observational knowledge is subject to a kind of justification by other facts.

McDowell and Brandom both recognize something called “observational knowledge”, but Brandom thinks that it necessarily involves appeal to claimed non-epistemic facts, whereas McDowell wants to broaden the concept of epistemic facts enough to be able to say that observational knowledge can be justified by appealing only to epistemic facts. I would prefer to say, observational judgments are subject to a kind of tentative justification by other judgments.

McDowell says that acquiring knowledge noninferentially is also an exercise of conceptual capacities. This clearly implies a noninferential conception of the conceptual, and seems to me to presuppose a representationalist one instead. This has huge consequences.

He says that the space of reasons must include noninferential relations of justification, which work by appeal to additional facts rather by inference. But where did those facts come from? In light of Kant, I would say that we rational animals never have direct access to facts that just are what they are. Rather, if we are being careful, we should recognize that we can only consider claims and judgments of fact, which may be relatively well-founded or not. But appeal to claims of fact for justification is just passing the buck. Claims of any sort always require justification of their own.

As an example, McDowell discusses claims to know that something is green in color. As non-inferential justification in this context, he says one might say that “This is a good light for telling the colours of things by looking” (p. 18). That is fine as a criterion for relatively well-founded belief, but that is all it is.

A bit later, he adds, “I can tell a green thing when I see one, at least in a good light, viewed head-on, and so forth. A serviceable gloss on that remark is to say that if I claim, in suitable circumstances, that something is green, then it is” (p. 19).

This is to explicitly endorse self-certification of one’s authority. It is therefore ultimately to allow the claim, it’s true because I said so. I think it was a rejection on principle of this kind of self-certification that led Plato to sharply distinguish knowledge from belief.

As Aristotle pointed out in discussing the relation between what he respectively called “demonstration” and “dialectic”, we can apply the same kinds of inference both to things we take as true and to things we are examining hypothetically. We can make only hypothetical inferences (if A, then B) from claims or judgments of A; we can only legitimately make categorical inferences (A, therefore B) from full-fledged knowledge of A — which, to be such, must at minimum not beg the question or pass the buck of justification.

The great majority of our real-world reasoning is ultimately hypothetical rather than categorical, even though we routinely act as if it were categorical. One of Kant’s great contributions was to point out that — contrary to scholastic and early modern tradition — hypothetical judgement is a much better model of judgment in general than categorical judgment is. The general form of judgment is conditional, and not absolute.

I think it’s fine to include beliefs, opinions, and judgments in the space of reasons as McDowell wants to do, provided we recognize their ultimately hypothetical and tentative character. But once we recognize the hypothetical and tentative character of beliefs, I think it follows that all relations within the space of reasons can be construed as inferential.

I don’t think contemporary science has much to do with so-called observational knowledge of the “it is green” variety, either. Rather, it has to do partly with applications of mathematics, and partly with well-controlled experiments, in which the detailed conditions of the controls are far more decisive than the observational component. The prejudice that simple categorical judgments like “it is green” have anything to do with science is a holdover from old foundationalist theories of sense data.

I would also contend that all putative non-space-of-reasons intelligibility ultimately depends on space-of-reasons intelligibility. (See also What We Saw.)