People do tend to default to the idea that causality is a mechanism that underlies things, and that this mechanism involves physical clunking of some kind. As in this recent comment:
[H]ow can we say that the object called Tim Morton and the hyperobject (assemblage) called ‘global warming’ don’t actually ‘touch’?
But as I shall argue in Realist Magic, causality is an aesthetic event that floats ontologically on top of objects, in between them. Touching in this sense is a purely aesthetic event. There’s not all that much difference between a billiard ball touching a billiard ball and me being touched affectively.
Of course I can’t concede that objects “touch” or “don’t touch” in the way described. To do so would be to subscribe to a very different ontology. Furthermore, I think my ontology is more congruent with the best that we know about physical reality, than clunk causality is.
At a profound level, touching registers a failure to engage, a non-touching. Touching, which is what a billiard ball perceives when a billiard ball smacks it, is at a quantum level the failure of particles to bust through resistance wells in molecular lattices. When something touches something, even when it seems to penetrate that something, it’s not really fusing with it. Its quanta are failing to fuse with it. That’s what touching is.
Touching, no matter how intimate, involves a necessary aesthetic distance. A faint echo of this is found in metaphor, in which two unlike things are brought close—but not so close that they become the same thing, otherwise metaphor would cease to operate. And in metonymy, in which relations of contiguity imply distances.
People usually think of causality as a clunk that breaks through the aesthetic screen, like Doctor’s Johson’s boot. I argue that this kind of clunking is one aesthetic phenomenon among many. I am touched, for instance, right at this very moment, by gravity waves emanating from the beginning of this universe. A chemical solution can be touched by a catalyst. Soft tissue is touched by high energy photons such as gamma rays, giving rise to mutagenic effects.
Many phenomena are nonlocal, such as what I perceive when global warming causes my eyes to itch. Many are nonlocal in a strong sense (quantum theoretical), such as the ways fruit flies smell or the way birds navigate. In no sense given above is physical touching involved. The opposite in fact: and this is what makes these processes all the more intimate.
To make physical proximity in 3D space the one sole true metaphor (or anti-metaphor) of causality is to think that Doctor Johnson’s boot has more efficacy than a gravity wave. I doubt it.