Gedankenexperiment or just a flight of fancy?

Abstract

What’s faster than the speed of light? The speed of thought they say. Not in the strict sense of metres per second taken for an impulse to travel down a neuronal axon, but in metaphor. For in an instant, the human mind can transport itself from terra firma to the farthest reaches of the galaxy, zoom into the tiniest organelle in the tiniest prokaryote, or even just jump onto some entirely alternate plane of reality. Much faster than any old light ray ever could. ‘There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy’. True, Prince Hamlet, no doubt. But Horatio’s philosophy can still go a long way and it can get there pretty fast. You may at this point be asking what does this have to do with Medicine and the empirical sciences? ‘All sounds a bit wishywashy, frankly . . . ’ And this is where I become sacrilegious; for may haps, in our never-ending battle to unearth every medical scientific mystery the universe holds, in this brave new era of evidence-based medicine, with all its correctness and methodical beauty we have lost from our armoury a most formidable weapon; the thought experiment. The most famous thought experiments, or Gedankenexperiments as the phrase popularized by Ernst Mach goes, are arguably those that developed into Einstein’s theory of Special Relativity and Newton’s theory of Gravity. Moments of genius in the history of Man. The latter theory was later proved by other empirical means of course, but their established use and the scientific celebrity they achieved made the use of these Gedankenexperiments invaluable tools in the physical sciences. However, the earliest recorded full account of a thought experiment comes to us from the writings of a physician rather than a physicist. A patriarch of modern medicine. One who originally described the contagious nature of tuberculosis and wrote on and propounded the Germ theory long before a miasmatic Europe finally caught ‘wind’ of it some eight centuries later. Ibn Sina or Avicenna as he is known in the West provides us the first full elucidation of a thought experiment with his ‘Flying Man’ description. A tradition of scientific method then started by a medic. Fast forward to today. In a modern world, is there any room for thought experiments to drive health policy? John Rawls’ work on distributive justice, which so intimately influences many of the principals of modern public health philosophy and practice, is itself based on a thought experiment. The Original Position thought experiment he describes in his book A Theory of Justice is used to justify and explain the system of distributive justice that so many health professionals now take as their ideal model for healthcare. Is there room then, on the basis of logical arguments and intuition alone, for decisions to be made that could potentially affect the health of large numbers of people? Or does every health proposal always have to come with the requisite bundle of randomized controlled trials and cost analyses in tow? Without exception? Surely, sound empirical evidence being a function of time, funding, necessity, popularity and the appropriately trained and motivated researcher is not always feasible. Does the entire process ever cause unnecessary delay or perhaps even stifle scientific development? Time then, to examine a case in point. Thought experiments all follow a methodology that is a priori and so are conducted wholly in the mind without the use of observation or physical experiment. They have proved invaluable in the discovery of new knowledge and in developing concepts in a wide variety of fields from philosophy and metaphysics, to law, mathematics and the natural sciences. As such, they have been divided into many subcategories depending on the particular method employed and discipline for which they are being adapted. As philosophers sometimes disagree on the very nature of thought experiments and often conceptualize them differently, several taxonomies have evolved for classifying them. For our purposes, let us construct our thought experiment using reductio ad absurdum, a model of apagogical logic where a proof by contradiction is made using an informal fallacy. Or