Philosophers often use reductio ad absurdum in metaphysics and philosophy of mind to make a point, to justify their position, or a thought experiment, or to reject a position or theory they do not like, but what is the point in all that if nature itself is absurd?
Consider this quote by Feynman from page 10 of QED: The Strange Theory of Light and Matter:
The theory of quantum electrodynamics describes Nature as absurd from the point of view of common sense. And it agrees fully with experiment. So I hope you accept Nature as She is — absurd.
What if a philosopher mounted a reductio ad absurdum on nature? would he be justified if his argument was sound?
Consider for example the problem of free will - one can imagine two philosophers who hold opposing views on free will, and who for many years reject each other's view using reductio ad absurdum; is that not absurd?
As an analogy, imagine two mathematicians who reject each other's coordinate systems for a sphere on account of including a singularity point, such as a north pole - let's call it the "absurdity" of a coordinate system - and they fail to realize that you cannot "explain" a sphere with a single coordinate system which is not "absurd" - you need at least two:
Singularities in familiar coordinates on the two-sphere can be eliminated by covering the sphere with two overlapping coordinate patches. (Gravitation, 1973, p. 12)
Or consider an example from philosophy of mind - Chalmers who is a property dualist employs a reductio ad absurdum in his famous fading and dancing qualia arguments to conclude that a robot may have conscious experience identical to his own (Wittgenstein would have rejected the whole thing on account of the absence of criteria of identity, but let us ignore that subtlety) - he admits that from his point of view as a steadfast dualist, his conclusion is highly counter intuitive - but robots with a dualist kind of qualia are not just counter intuitive - they seem to be absurd since their qualia are hopelessly epiphenomenal - their qualia can have no effect on the calculation mechanism, and they therefore have no way to "know" their qualia - that is, Chalmers arguably uses reductio ad absurdum to reject one absurdity for another.
It seems to me that if nature is absurd, then using reductio ad absurdum in metaphysics or philosophy of mind may be wrong and misleading - but nevertheless, philosophers continue to use it - maybe as someone who is stumbling through the dark and refuses to throw away a flashlight that ran out of batteries.
Wittgenstein says that philosophers mislead themselves into confusions by misusing language, and that philosophy should be done differently - in essence describing and surveying problems rather than trying to explain them:
we may not advance any kind of theory. There must not be anything hypothetical in our considerations. All explanation must disappear, and description alone must take its place. And this description gets its light -- that is to say, its purpose a from the philosophical problems. These are, of course, not empirical problems; but they are solved through an insight into the workings of our language, and that in such a way that these workings are recognized -- despite an urge to misunderstand them. The problems are solved, not by coming up with new discoveries, but by assembling what we have long been familiar with. Philosophy is a struggle against the bewitchment of our understanding by the resources of our language. (PI §109)
Do you know of philosophers who address this problem?
you might also enjoy the following very funny video of Feynman explaining nature's craziness to students - https://youtu.be/eLQ2atfqk2c?t=24m2s - the lectures themselves are very interesting - after watching them two years ago I realized for the first time how holograms actually work.