Regarding reality: some consequences of two incapacities.

A person cannot empirically determine whether they are awake or dreaming because any statistical test of reality (e.g., checking for bizarreness) requires baseline measurements that could be tampered with by the same processes generating the dream or simulation. Cryptographic defenses also fail, as reality modification within a dream can extend to verification keys or declared outcomes. Given this double predicament, the rational course is to take reality at face value. Even insights like Buddhist enlightenment are ultimately unreliable for the same reason, though one must be aware of this principle—which may be impossible in altered states like dreaming or religious experience.

Study at a glance

Abstract

By what empirical means can a person determine whether he or she is presently awake or dreaming? Any conceivable test addressing this question, which is a special case of the classical metaphysical doubting of reality, must be statistical (for the same reason that empirical science is, as noted by Hume). Subjecting the experienced reality to any kind of statistical test (for instance, a test for bizarreness) requires, however, that a set of baseline measurements be available. In a dream, or in a simulation, any such baseline data would be vulnerable to tampering by the same processes that give rise to the experienced reality, making the outcome of a reality test impossible to trust. Moreover, standard cryptographic defenses against such tampering cannot be relied upon, because of the potentially unlimited reach of reality modification within a dream, which may range from the integrity of the verification keys to the declared outcome of the entire process. In the face of this double predicament, the rational course of action is to take reality at face value. The predicament also has some intriguing corollaries. In particular, even the most revealing insight that a person may gain into the ultimate nature of reality (for instance, by attaining enlightenment in the Buddhist sense) is ultimately unreliable, for the reasons just mentioned. At the same time, to adhere to this principle, one has to be aware of it, which may not be possible in various states of reduced or altered cognitive function such as dreaming or religious experience. Thus, a subjectively enlightened person may still lack the one truly important piece of the puzzle concerning his or her existence.