Consider a mountain: the thinking of
this mountain entails (a) that there is already a mountain to be thought, whatever its
nature; and (b) that the causes of the existence of the mountain must also be involved
in the thinking of the mountain.
Hamilton Grant, Does Nature Stay What-it-is?: Dynamics and the Antecendence Criterion, p. 82
Interesting spelling out and proposed solution to the problem of ground in (one of) Hamilton Grant's contribution to The Speculative Turn. The problem is that ground seems to point both at logical connections (or, broadly, moves within the space of reasons) and material connections (something typically like causes and effects). But, as Kit Fine says (in his Some puzzles of ground, Notre Dame Journal of Formal Logic 51 (1):97-118, 2010), ground is a notion that seems logically faulty but is invaluable enough to be nevertheless embraced and not discarded. The Fichtean solution, as Hamilton Grant presents, is to locate ground in action and action solely within the space of reasons. Such solutions (he mentions few others that would amount to the same limitation of ground to reason) miss the bite of the principle of sufficient reason: it has to rule over natural contingencies otherwise it leaves everything beyond reason out of its scope. Grant's own solution is to claim that because nature is itself potentia, it is the sufficient reason for all contingencies. Physical particulars are always ungrounded and yet all of them find an antecedent in the (sort of) pool of possibilities which is matter (what constitutes nature).
The solution points at a continuity between grounding relations in the space of reasons (thinking, making inferences, making judgements) on the one hand and causes in nature in the other. Hence, as in Davidson's own solution to us being possibly wrong in all of our particular beliefs about the world, he holds that a thought of the mountain is caused by the mountain. In Davidson, sceptical objections, such as the possibility of us being brains in a vat or Davidson's own swampman example (he imagines a swamp replica of himself having his usual thoughts after his death and asks whether these thoughts were caused by the things they are about), arise. But Grant has a way to dismiss them. My thinking of the mountain is caused by the mountain, but could have been caused by anything else - particular events are accordingly ungrounded. The ground for them is nature. But then again, this is the nature of contingencies in the world and has nothing specifically to do with the border between the realm of nature and the space of reasons. Things always could have gone differently in nature, as it is potentia - a pool of uncountable possibilities. The border between the realm of nature and the space of reasons is subject to contingencies in the same way as a geological movement could have given rise to different surfaces.
His solutions illuminates other aspects of the border between the realm of law and space of reasons and some other varieties of sceptical anxiety. McDowell's own (somehow Fichetean) way of conceiving the space of reasons as something that is not spinning frictionless in the void was to make it unbounded. That amounts to say that it had no borders with the realm of law but rather encompassed it. Nature becomes rational, in his case, thoroughly subject to concepts - made of thinkables. It is his partial re-enchantment of nature as a response to the idea that the realm of nature is no more than a realm of laws. This idea is hostage to the notion that nature is determinate, actual and composed of necessary (universal) regularities. McDowell's re-enchantment has that nature is fully thinkable. Grant's re-enchantment has that thinking itself is natural - doubting is brought about by contingency, which is itself natural. Matter, as potentia, holds together the realm of nature - itself active, vibrant, animated and not lawlike - and the space of reasons.