Les idées expérimentales, comme nous le verrons plus tard, peuvent naître
soit à propos d'un fait observé par hasard, soit à la suite d'une tentative expérimentale,soit comme corollaires d'une théorie admise. Ce qu'il faut seulement noter pour le moment, c'est que l'idée expérimentale n'est point arbitraire ni purement imaginaire ; elle doit avoir toujours un point d'appui dans la réalité observée, c'est-à-dire dans la nature. L'hypothèse expérimentale, en un mot, doit toujours être fondée sur une observation antérieure. – Claude Bernard

LI has been pondering various ways of approaching the multitudinous subject of the thought experiment, soi disant. We have gotten some mail on this topic. The mail was puzzled – as in, what the hell is our point? So before we trace the geneology back to Socrates (both as mythmaker and myth), and make the usual grand historical tour in a paragraph, perhaps we should hatch an argument out of a diffuse discontent.

Okay. Fair enough. What is the problem, then, with thought experiments?

Here it is: the problem is that thought experiments often seem more like experimental designs than experiments. When Popperians (of the Karl, not the Mary, persuasion) talk of conjecture and refutation, or when Bernard talks of observation, or when we use that experiment on circadian rhythm that we pointed to in our last post, all are trying to indicate that experiment has a middle, material term. That material term – the content of the experimental process itself – is such that it creates a distinct point of reference different from the experimental design. I might say to myself, say, what are the circadian rhythms of human beings like? And I might then devise a way of denying human beings sunlight as a clever way of extracting those rhythms. But until I have done the work of actually plunging the human beings into darkened chambers or subterranean caverns, I haven’t performed the experiment. Whereas performance and experimental design seem to collapse together when, for instance, I want to make the argument that artificial intelligence is impossible to prove, and I come up with a story about a machine, an input of Chinese symbols, a person within the machine, and an output of English words.

My argument, then, is that a thought experiment lacks a performative dimension. And that depends, in turn, on the idea that thought doesn’t perform. I don’t like that supposition, but for the moment, this is the side I’m taking. Until I wiggle out of it.

Now, defenders of the thought experiment often use early ‘thought experiments in science and philosophy to make the point that there has always been something “like” the thought experiment. What they don’t do is ask what these early “thought experiments” were called by their creators. LI suspects that the conjunction of thought and experiment, as a lexical event is part of the prestige accrued by the experiment during the nineteenth century. When Zola, reading Bernard, decides to apply Bernard’s “experimental method” to writing – when he writes the “Roman experimentale” – we are crossing a threshold. It is about that same time that Mach coins the term “Gedanken-experiment.”

Before that moment, there were riddles, problems, demonstrations, etc. etc. Take the the Molyneux problem. When Locke considers it in the Essay on Human Understanding, he doesn’t compare it to an experiment – although Locke was very familiar with experiments, of course. The end of the seventeenth century was a veritable Island of Laputa, filled with experiments and projects.

This is Locke:
“So that from that which is truly variety of shadow or colour, collecting the figure, it makes it pass for a mark of figure, and frames to itself the perception of a convex figure and an uniform colour; when the idea we receive from thence is only a plane variously coloured, as is evident in painting. To which purpose I shall here insert a problem of that very ingenious and studious promoter of real knowledge, the learned and worthy Mr. Molyneux, which he was pleased to send me in a letter some months since; and it is this:- "Suppose a man born blind, and now adult, and taught by his touch to distinguish between a cube and a sphere of the same metal, and nighly of the same bigness, so as to tell, when he felt one and the other, which is the cube, which the sphere. Suppose then the cube and sphere placed on a table, and the blind man be made to see: quaere, whether by his sight, before he touched them, he could now distinguish and tell which is the globe, which the cube?" To which the acute and judicious proposer answers, "Not. For, though he has obtained the experience of how a globe, how a cube affects his touch, yet he has not yet obtained the experience, that what affects his touch so or so, must affect his sight so or so; or that a protuberant angle in the cube, that pressed his hand unequally, shall appear to his eye as it does in the cube."- I agree with this thinking gentleman, whom I am proud to call my friend, in his answer to this problem; and am of opinion that the blind man, at first sight, would not be able with certainty to say which was the globe, which the cube, whilst he only saw them; though he could unerringly name them by his touch, and certainly distinguish them by the difference of their figures felt. This I have set down, and leave with my reader, as an occasion for him to consider how much he may be beholden to experience, improvement, and acquired notions, where he thinks he had not the least use of, or help from them. And the rather, because this observing gentleman further adds, that "having, upon the occasion of my book, proposed this to divers very ingenious men, he hardly ever met with one that at first gave the answer to it which he thinks true, till by hearing his reasons they were convinced.”

This has all the hallmarks of the kind of thought experiments that analytic philosophers go nuts over – in fact, one of those t-e’s, Frank Jackson’s Mary in the black and white room, is a variant. Molyneux was a mathematician, and the terms in which he couches his “problem”, the style, is a peculiar blend of mathematics and casuistry. Molyneux seems convinced that the answer to his problem lies in the reasons he gives for answering the problem. That bears a relationship to experiment, insofar as experimenters have reasons, but those reasons are hypotheses which, at least in the Baconian tradition, are put to some kind of test. That test is the performative dimension. Is the giving of reasons – is argument – the same thing as a test?

The grooviness of the Molyneux problem is that it did achieve performance – that is, there were operations on aveugles de naissance during the 18th century. One of Diderot’s most famous essays, Lettre sur les aveugles, is on just such an operation.

LI should note one amusing result of this notion of performativity. From the perspective of the history of the experimental method, the Schroedinger's Cat thought experiment has a unique place. The experimental design is such that its performance as an experiment would destroy its result as an experiment. Because we have learned to look at these things in terms of observation, we have ignored the performative dimension in which observation is embedded -- we have ignored, in other words, how experiments function. But if we restore the performative dimension to its place in a theory of experiment, then the Schrodinger's cat thought experiment -- and others of its kind meant to show the peculiar qualities of quantum mechanics -- should provide us with limit cases in which the form of experiment generates its own negation qua experiment. This is to be distinguished from thought experiments that are merely physically impossible, or that involve entities like possible worlds. The Schroedinger's cat thought experiment implies a contradiction in the very structure of the experimental method.

And that is all LI will say about that topic -- we've noticed that the amount of bs generated by a lay person speaking of quantum physics is in direct proportion to said lay person's ignorance. This could certainly be, if not a law, at least a rule of thumb.