In Mind and World, McDowell seeks to exorcise an anxiety relating to the possibility of empirical content that would threaten to close down the option of giving an account of rational constraint by the world that proceeds in the foregoing way. McDowell’s strategy is repeatedly mischaracterised, so it is important to accurately state his aims: to hold onto a minimal empiricism and the idea that the logical space of law is different in kind than the logical space of reasons.
The first desideratum is a version of Quine’s idea that experience must constitute a tribunal that rationally constrains our thoughts. This thought is that, without the sort of constraint that through experience allows the world to reveal to us what we should think, then the very idea that thought is about the world at all must be relinquished. This is because for a belief to possess empirical content is for it to purport to be about the world in some way, and this means that it is essentially something that can be appropriately or inappropriately held to be the case. Given our natures as embodied spatio-temporal agents, it is through experience that the world can exercise a rational constraint upon us. If we are forced to give up this sort of rational constraint then the idea that thought can bear upon the world at all is also threatened.
The second desideratum builds upon but importantly modifies Sellars’ thoughts about the logical space of reasons. For Sellars, when we talk about reasons (for example, discussing claims to knowledge or justification) then we invoke a characteristic mode of intelligibility that can be contrasted with the sort of intelligibility invoked when we explain one thing by showing how it is a causal consequence of another. The logical space of reasons supports normative relations such as implication, entitlement, probabilification and so on which can be contrasted with these causal notions. ...
McDowell thinks we will get into trouble if we identify the logical space of laws with the logical space of nature. For those, such as Brandom, Rorty and Davidson, who appreciate Sellars’ insight that the logical space of reasons constitutes an important mode of explanation that is irreducible to the logical space of laws, the problem is that if these two logical spaces are dichotomous, and nature is the logical space of laws, then it seems that normative relations between nature and our reason-governed practice are impossible. This threatens minimal empiricism, which depends upon rational constraint from the world, and this in turn threatens to make empirical content unintelligible, as we have seen.
However, McDowell thinks that we can deny that the logical space of nature is identical to the logical space of laws. He admits that the huge success of the hard natural sciences is undeniable and that these sciences rely on a nomothetic model of explanation in which phenomena are elucidated by subsuming them under the strict causal laws. However, he thinks that only a misplaced scientism would force us to say that this is all there is to nature. If this separation of the logical spaces of nature and law is possible then we ought to be able to hold onto both the Quinean and Sellarsian insights, and so thereby retain the conception of a reason that is authoritative independently of our treating it as such...
Although McDowell believes that socialisation is essential to the process of “having one’s eyes opened to reasons at large by acquiring a second nature,” he does not think that this should lead us down an anti-realist path. In fact, he goes as far to characterise his position as a ‘naturalised platonism.’ The sense in which McDowell’s attitude towards reasons is platonistic is that what counts as a reason for something is not specifiable by reference to facts about us that are specifiable prior to characterising us in terms of the space of reasons. This represents McDowell’s anti-reductionist tendencies, emphasising the autonomy of the space of reasons from the sort of explanation offered by the natural sciences.
However, from the other direction, this platonism is essentially naturalised because reasons are the sort of things that can be grasped by mature humans. Nor is this merely a lucky coincidence but something pivotal to the idea that mature humans are agents who have the world in view at all. The key to understanding this thought is to recall that McDowell’s response to Kant involves championing the idea that the world is always-already apt for conceptualisation and thus essentially reason-giving for us.