Physics vs feeling: Can I really touch anything?

Mouse asked:

I have recently heard that, according to physics, you can never actually touch anything.

This seems clearly false and I feel it should be refuted with philosophy (if not physics).

Can you comment on this?

p.s. See for example which seems to claim that, according to physics, you can never actually touch anything.

Answer by Jürgen Lawrenz

A philosopher can easily get tired of all these ultra-reductionist and ultimately futile assertions. One begins to wonder what they really seek to show (or prove?), or whether it’s merely one-upmanship on naive auditors.

After all, it must have been obvious to Caveman that the lizard on his hand can’t see him, and that conversely he can’t taste the food this creature eats. So what? Yet the creature feels something of the man’s skin, maybe a kind of leathery landscape that allows it to sink its claws in to hold fast; and the man would feel the pinpricks as well as the warm soft texture of the lizard’s belly. Between the two a connection is established, and that’s what we need to understand about our feelings – not that they are unreal, figments or hallucinations. Fact: there is rapport here that conveys a specific type of information to both nervous systems.

Of course you can place a microscope with stupendous magnification powers on this scene, when you would observe nothing but molecules tumbling around in some oily slosh. Entertaining for a while, but not informative to your heartbeat with the wonder of it. Going further down into the realm of physics changes everything again, because here even the molecules are so big that (by all appearances) you could drive a fleet of trucks through the spaces between them. Except that you can’t see this at all, because there is no way of making it visible. This is where those wonderful coloured graphs in our textbooks deceive us, making us believe that neutrons and protons and electrons and the rest of the subnuclear bric-a-brac are hard physical things, whereas in reality there is nothing hard or soft to be found.

So what could your physicist explain? Nothing much that is meaningful to the animal/human context. In particular: He could not deduce from either the chemical slosh or the scattering of neutrons what they might produce in terms of sensations. He and you need the experience of a physical touch first, before any physics elaboration is possible. Without this prior knowledge, it would not be possible to conceive of a moment or location when sensation arises; and the sad truth is, that even with this experience behind us, a billionfold swarm of elements still does not yield up the information that physics pretends to convey. And so, to be blunt about it, the message of physics on whether touch is real or not, ends up being gobbledygook.

The message from chemistry is slightly more respectable, because chemists deal with things to which we can put a measuring gauge through a microscope. But again: size is of the essence – for in the region of molecules which sport only a few million chemical bits and pieces, you can see something that vaguely resembles cause and effect being realised in the macroscopic world. But this could occur in a Petri dish as well as your fingertip, so that we are still no wiser on the question.

Consider, however, that some of these molecules are alive and act/react the same way cavemen and lizards do. Evidently this is where sensing becomes a phenomenon to which we can relate, namely with microbes initiating a sense of touch, from which we learn that all sensations are variants of the basic sense of touch.

Many steps up the evolutionary ladder, we discover that hearing is the impact of a train of air-driven molecules on your eardrum, and that taste is the tongue’s analysis of physically deposited chemical substances on its surface. The brain, which has evolved to recognise sensory impact as so many species of molecular vibrations, knows how to separate them and pipes this information into your consciousness in the form of subjective feelings.

This subjectivity does not, however, diminish its reality. Your and my reality is actual touch, hard or soft, hot or cold, rough or smooth. How wonderful to be told that all this is due to the energetic flurry of chemical elements and their interpenetration. That’s knowledge too. But emphasising the distance between the atoms of my fingertips and my tabletop for an argument that it precludes actual touch is non-information, because it copulates quite illicitly two different and incompatible dimensions of existence.

The only virtue, in the end, is that chemical know-how enables us at times to bridge these dimensions indirectly, i.e. by administering anaesthetic drugs. Yet even this is not a valid component of the argument, since it only numbs the body’s receptors. Blind people know about this and navigate with the help of sticks, exchanging one touch for another.

To end, a couple of curious instances on this “physics vs feelings” dichotomy.

(1) The poet Goethe, who knew a thing or two about art, wrote up a theory of colour. Some years later it was demolished in the name of science by the physicist Helmholtz. Who was right? Most people incline towards Helmholtz, but there have always been unrepentant lovers of art who ask the more relevant question, “what use is the physics theory to artists?” Answer: None. For colour is a sensation that provokes inter alia an emotional reaction. So does the pin-prick which, according to your physicist, involves no immediate touch.

(2) Arthur Eddington wrote on page 6 of his book The Nature of the Physical World that “the table I write on is mostly empty space”. How so? “There are innumerable electric charges rushing about, but their combined bulk amounts to less than a billionth of the table’s substance”. But (he says) he still maintains his complete trust in physical reality of the table, leaning on it while writing without expecting the billions of interstices to cause its collapse.

Thus, finally: Immediate touch is nothing other than a question of how greatly this event is magnified when you look at it. And it stands to reason that at a certain level of magnification, not only the sense of touch, but the meaning of this event disappears.

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