“This is an external world, sense perception is reliable, I am not a brain in a vat, my faculty of reasoning is reliable [...], memory is reliable.”[1]
What does it mean to be “normal”? When we say that a behavior is typical, or a mind is well-functioning, are we really describing a standard that expects the absolutes, or a pattern that carries some fluidity? It appears, rather interestingly, that our inner narratives and sense of coherence emerge from somewhere between what is and what could or might be. This concept troubles our notion that perception is simply a passive reception of the world. In reality, both ancient philosophy and modern neuroscience seem to point us toward a different possibility altogether: that our mind is always doing more than receiving.
Plato’s allegory of the cave alludes to the modern idea of an actively adapting mind, as sensual perceptions do not convey stable truths but information that can confuse the mind. In the allegory, prisoners are chained in a cave since childhood, with their necks and legs fettered. Light is provided by a fire burning far above and behind them. Between the prisoners and the fire is a low wall, along which people walk by and carry artifacts above it. As the prisoners cannot turn their heads, they can only see what is in front of them: shadows of the artifacts cast by the firelight.[2] Having become accustomed to seeing shadows, the prisoners conform to what they see and organize their observations into a coherent pattern of anticipation. They interpret the shadows through an internal model shaped by habit and prior beliefs, perhaps even formulating a narrative to rationalize the shadows’ existence. Plato then simulates a condition in which the prisoners are released from their bonds and can see the light and the artifacts themselves.[3] Because of these new perceptions, the mind will challenge its prior framework and eventually build a new system that expects light to create the shadows the prisoners have previously seen. In the allegory, Plato frames the turning toward light as a process of grasping the forms. But if we detach the structure of the allegory from his metaphysics, other interesting questions surface: Could it be that our minds are living only to see the shadows again and again? Is it possible that our brain survives only by constantly turning toward the light?
More generally, Plato believes that the soul is formed by three parts: reason, spirit, and appetite. He describes internal harmony as an ideal condition, though this ideal is itself already a kind of expectation, a prediction about how one’s impulses ought to behave. In his Phaedrus, Plato likens the soul to the natural union of a team of two horses and their charioteer, with one horse beautiful and good, and the other the opposite.[4] The rational part of the soul, accordingly, drives the spirited and appetitive parts. At first glance, its role appears to be a static, top-down commander, prevailing over the soul’s other parts. But this is far from true. Reason must be bounded; otherwise, the prisoners in the cave could have reasonably deduced the very world they were trapped in. Something else constrains and shapes reason. In Plato’s architecture, reason does not operate on raw truth but on the perceptual material available to it. Its ignorance is simply a consequence of its inputs. Reasonably, that something which limits reason is perception. The system within which reason operates is never free-floating. It is always guided, and sometimes misled, by the perceptual frame it inhabits. Spirit and appetite sometimes prevail because perception filters and limits what reason can foresee. Reason alone does not stop anyone from smoking or drinking; it simply anticipates consequences within an incomplete or often biased model. If we examine the relationship between the soul’s parts more closely, reason begins to look more like a simulator: it expects the swell of appetite, tempers the volatility of spirit, and imagines possible outcomes before they happen. In this sense, reason weighs and negotiates among the futures it predicts. And if Plato’s reason is already functioning as a kind of predictive negotiator rather than an absolute ruler, what happens when we turn to thinkers who center this uncertainty and our ever-updating predictive systems?
A student of Plato, Aristotle shifts the focus from internal harmony to the cultivation of virtue in practice. For him, eudaimonia[5] is achieved not through abstract contemplation alone but through an integration of reason with experience. This involvement of reason, importantly, dictates the participation of the ability to expect outcomes, to recognize which futures are likely to occur given an action, and to decide which of the many futures best balances one’s character with one’s situation. Acting well is, under this light, a weighing of counterfactuals before they occur. Centuries later, Hume extends and complicates Aristotle’s account by emphasizing that moral judgment originates primarily in sentiment rather than in reason alone. Reason, he contends, helps navigate means to ends shaped by feeling and social norms, but it does not determine the value of those ends. Humans, he observes, do not inhabit a realm of pure reason but, instead, live within flexible webs of expectation formed by custom, sentiment, and social exchange.[6] Hence, what we call “normal” behavior is better understood as a series of interactions among our inferences, expectations, and perceptions.
If the moral life is already a matter of expectation and inference for Hume, neuroscience provides further molecular evidence for this view. A vivid example is the dopamine pathway. Though long thought of as simple “reward circuits,” they turn out to record prediction errors, tracking the discrepancies between what the brain expects and what actually occurs.[7] Importantly, this feedback mechanism allows organisms to refine their internal model of the world and continually test and revise the futures they have already imagined. From a broader perspective, we may consider Karl Friston’s free-energy principle: the brain survives by minimizing surprise through the generation of predictions expansive enough to shrink it.[8] Springing from these observations, perception, then, becomes a testing dataset for the hypotheses we generated. Anil Seth further develops this idea with his notion of counterfactual richness. Seth notes that the brain does not simply record what is there, but constructs experience out of a dense field of possibilities: if I move, this will happen; if I speak, that expression will shift.[9] Thus, what we term “abnormal” behaviors are simply a chosen future by a brain whose filtering mechanisms generate different expectations and thus a differently experienced world. Understood this way, normality becomes the capacity of a predictive organism to generate coherent expectations and update them in a way that remains intelligible within its social and environmental setting.
Once perception is understood as this active testing of the world to see which imagined futures it confirms, the question naturally returns to how these predictions acquire their shape in the first place. What governs the filters through which certain futures appear likely, others impossible, and still others morally necessary? Artificial intelligence (AI) offers a surprisingly clarifying analogy here. Just as a machine-learning model constructs its “world” by filtering data through architecture and training loops, humans perceive moral situations through filters formed by experience, culture, temperament, and memory. Let’s consider moral dilemmas. Two people facing the classic trolley problem might appear to make opposing decisions because their values differ, but in reality, they are responding to entirely different dilemmas, never the same one. Oneperson’s mind imagines a future in which pulling the lever is an act of inevitable necessity; another person’s mind simulates a future in which intervening feels like a terrifying overreach. Their predictive machines, or their brains, differ because the filters that generate possibilities diverge. Their different decisions essentially reflect a deeper gap between the futures their minds spontaneously imagine. In this light, moral “normality” emerges from the active negotiations among predictive mechanisms, lived and culturally programmed histories, and collective myths that teach us which imagined futures feel permissible, and which feel unthinkable.
In the end, normality becomes a pattern of coherence produced by our predictive minds, while abnormality arises from the predictive errors and the social world that teaches us which futures feel possible. Eventually, normality ceases to be a static condition and becomes the equilibrium of a mind forever updating its models of the possible.
[1] Anthony Brueckner, “Hinge Propositions and Epistemic Justification,” Pacific Philosophical Quarterly 88, no. 3 (2007): 285-87, https://doi.org/10.1111/j.1468-0114.2007.00292.x.
[2] C. D. C. Reeve, trans., Plato: Republic (Indianapolis: Hackett Publishing Company, 2004), 208
[3] Reeve, Plato: Republic, 209.
[4] Plato, “Phaedrus,” trans. Alexander Nehamas and Paul Woodruff, in Plato: Complete Works, ed. John M. Cooper and Douglas S. Hutchinson (Indianapolis: Hackett Publishing Company, 1997), 524.
[5] Eudaimonia is an ancient Greek concept often translated as “human flourishing” or “living well.” It represents the highest human good in Aristotle’s ethics.
[6] David Hume, An Enquiry concerning the Principles of Morals, comp. John Mamoun and Charles Franks (1777), digital file.
Note that while each individual brain constructs its own predictive model of the world, these models do not develop in isolation. Social norms, cultural practices, and shared narratives act as external constraints that shape which imagined futures are reinforced, punished, or deemed permissible.
[7] Kelly M. J. Diederen and Paul C. Fletcher, “Dopamine, Prediction Error and Beyond,” The Neuroscientist 27, no. 1 (2021): 30-46, https://doi.org/10.1177/1073858420907591.
[8] Karl Friston, “The Free-Energy Principle: A Unified Brain Theory?” Nature Reviews Neuroscience 11, no. 2 (2010): 127–38.https://doi.org/10.1038/nrn2787.
[9] Gaia Vince, “Being You by Professor Anil Seth Review—the Exhilarating New Science of Consciousness,” The Guardian, last modified August 25, 2021, https://www.theguardian.com/books/2021/aug/25/being-you-by-professor-anil-seth-review-the-exhilarating-new-science-of-consciousness.
Bibliography
Aristotle. Nicomachean Ethics. Translated by W. D. Ross. Internet Classics Archive. Accessed March 25, 2026. https://classics.mit.edu/Aristotle/nicomachaen.html.
Brueckner, Anthony. “Hinge Propositions and Epistemic Justification.” Pacific Philosophical Quarterly 88, no. 3 (2007): 285-87. https://doi.org/10.1111/j.1468-0114.2007.00292.x.
Diederen, Kelly M. J., and Paul C. Fletcher. “Dopamine, Prediction Error and Beyond.” The
Neuroscientist 27, no. 1 (2021): 30-46. https://doi.org/10.1177/1073858420907591.
Friston, Karl. “The Free-Energy Principle: A Unified Brain Theory?” Nature Reviews Neuroscience 11, no. 2 (2010): 127–38. https://doi.org/10.1038/nrn2787.
Hume, David. An Enquiry concerning the Principles of Morals. Compiled by John Mamoun and Charles Franks. 1777. Digital file.
Plato. “Phaedrus,” translated by Alexander Nehamas and Paul Woodruff. In Plato:Complete Works, edited by John M. Cooper and Douglas S. Hutchinson. Indianapolis: Hackett Publishing Company, 1997.
Reeve, C. D. C., trans. Plato: Republic. Indianapolis: Hackett PublishingCompany, 2004.
Vince, Gaia. “Being You by Professor Anil Seth Review—the Exhilarating New Science of Consciousness.” The Guardian. Last modified August 25, 2021. https://www.theguardian.com/books/2021/aug/25/being-you-by-professor-anil-seth-review-the-exhilarating-new-science-of-consciousness.
