IN THEORETICAL AND PHILOSOPHICAL PSYCHOLOGY Regarding Reality: Some Consequences of Two Incapacities

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. A realist is simply one who knows no more recondite reality than that which is represented in a true representation. — Charles Sanders Peirce (Some Consequences of Four Incapacities, 1868) Is this the real life? Is this just fantasy? . . . Ooh yeah, ooh yeah Nothing really matters Anyone can see Nothing really matters — nothing really matters to me — Freddy Mercury / Queen (Bohemian Rhapsody, 1975) ∗Corresponding author: Shimon Edelman, Dept. of Psychology, Cornell University, Ithaca, NY 14853, USA. File generated on November 23, 2010 at 11:34. Warning: for reasons that will become apparent after reading this paper, all recollection of it may disappear from your memory after you finish reading it. 1 The seeds of doubt The suspicion that the world is not quite, or maybe even not at all, what it seems has a long history of being toyed with by those who are predisposed to metaphysical speculation. It also has a long history of being roundly rejected by practically minded people — a category that includes most off-duty metaphysicians.1 The present paper is an attempt to understand both the perennial philosophical appeal of questioning reality and people’s routine acceptance of reality at the face value, by considering metaphysical insights into this singularly important aspect of the human condition against the background of some recent developments in cognitive and computer sciences. A metaphysical doubt of reality may arise from such a common human experience as waking from a dream, surrounded by fleeting memories of another world that hint at the possibility of a deeper reality hiding behind waking life itself. Among the countless expressions of this experience, the one by Chuang Tzu (1968, ch.2, p.49), which dates back to the 4th century BCE, stands out: “Once Chuang Tzu dreamt he was a butterfly, a butterfly flitting and fluttering around, happy with himself and doing as he pleased. He didn’t know he was Chuang Tzu. Suddenly he woke up and there he was, solid and unmistakable Chuang Tzu. But he didn’t know if he was Chuang Tzu who had dreamt he was a butterfly, or a butterfly dreaming he was Chuang Tzu.” In Western philosophy, a succinct statement of the case for doubting reality is found in Discourse on Method by Descartes (1637, IV): “When I considered that the very same thoughts (presentations) which we experience when awake may also be experienced when we are asleep, while there is at that time not one of them true, I supposed that all the objects (presentations) that had ever entered into my mind when awake, had in them no more truth than the illusions of my dreams.” Between Chuang Tzu (or the butterfly that dreamed him) and Descartes, it would seem that philosophical inquiry has gotten to the bottom of the reality issue, and that no stone has remained unturned in the process. Science, however, keeps expanding its own range of inquiry, and each newly added field comes with its share of stones under which there lurk implications for, or even answers to, philosophical questions (and, often enough, new questions). The question of the nature of experienced reality and its veracity is a case in point: along with many others, this question’s import has been irrevocably transformed by the realization that a mind is made of computations, and that these computations construct a virtual reality. 2 The mind as a virtual reality machine Every physical process — that is to say, every process — in the universe computes something. Indeed, if a ripe apple falling from a tree and the planet from which the tree grows did not compute their trajectory with respect to each other, they would be at a loss as to how fast and which way to move (Edelman, 2008b). While this observation implies that minds too are essentially and literally, not metaphorically, computational, not every process qualifies as a mind. Succinctly put, a mind is a persistent bundle of computations over representations — state-space trajectories that reliably reflect, in a counterfactually consistent manner, the dynamics of physical processes that are external (that is, only weakly coupled) to the system that implements it. The arguments and evidence I hasten to remark that this observation merely echoes a line from Tlön, Uqbar, Orbis Tertius: “Hume noted for all time that Berkeley’s arguments did not admit the slightest refutation nor did they cause the slightest conviction” (Borges, 1962).