A true experiment is one where each subject is allotted to truly random conditions. In this sense, we cannot perform a true experiment. Never in the history of science has a true experiment been performed. Only the multiverse itself can be considered a condition of random allotment. If one could stand outside the many branches that remain spawned from every observation-like event, then a true experiment may be witnessed. Switch spin up to spin down and behold.
As researchers, we seek random allocation so that we can make strong inferences about causal relationships. The only reason for random allocation is because the subjects we deal with cannot be paused, copied, and pasted to a different condition. It is due to the makeshift nature of our subject clones that we are compelled to close our eyes and cast them in randomness. Randomness is the craving to recover the simple, the veil to hide the shame that we could not be gods.