Scientifically Invalidating Regret: The Decisional Entropy Illusion Theory

By Jeffrey DeSarbo, D.O., Neuropsychiatrist

Regret is one of the most persistent emotional burdens humans carry. It creeps in silently, then festers, often manifesting as rumination, self-criticism, or a haunting sense of having missed life’s “right path.” We all experience it: the job we didn’t take, the relationship we ended, the thing we said, or didn’t say. Regret is seductive in its simplicity. It tells us a story we want to believe: that if only we had chosen differently, life would be better.

But what if this emotional reflex, so widespread, so human, is based on a false premise? What if regret is not only psychologically corrosive but scientifically flawed? That’s the premise behind what I termed the Decisional Entropy Illusion Theory (DEIT): the idea that imagining better outcomes from past decisions is an illusion, one contradicted by laws of physics, principles of chaos theory, quantum mechanics, and other fields of both theoretical and applied science. In short, the notion that we could have acted differently and controlled the results is inconsistent with how the universe, both at macro and micro levels, actually works.

This paper presents a scientifically grounded, interdisciplinary framework for understanding why regret is not only futile but also fundamentally incompatible with the behavior of real systems. From thermodynamic energy transfer to butterfly effects and quantum indeterminacy, the sciences tell us a story that challenges the very structure of human regret and offers us a path forward grounded not in fantasy, but in mindful agency.

The Physics of the Mental Process

To understand why regret collapses under scientific scrutiny, we begin with thermodynamics: the physics of energy. Born out of 19th-century efforts to understand steam engines and heat transfer, the laws of thermodynamics have evolved into a set of fundamental principles used across disciplines, ranging from physics and chemistry to engineering and cosmology.¹

Given the significant inherent complexities, it is worth exploring how, even if rarely referenced, the laws of thermodynamics might still inform our understanding of psychology and neuroscience. This consideration reveals that, despite the challenges of quantification, the human brain is fundamentally a thermodynamic system: it consumes energy (primarily via glucose metabolism), produces heat, and manages entropy in the form of uncertainty and cognitive overload.²

Recent theoretical frameworks, such as Friston’s Free Energy Principle, propose that the brain works to minimize surprise and prediction error, an inherently thermodynamic process.³ Entropy has also been linked to models of psychopathology, suggesting that mental disorders may represent rigid, low-entropy attractor states that reduce uncertainty at the cost of adaptability. Mental fatigue, decision-making, and attention can be understood through energetic models, where cognitive effort is equated with energy expenditure. 

Mindfulness and emotional regulation may increase a system’s entropy tolerance, enabling broader and more adaptive mental states. As neuroscience and psychology integrate biological, computational, and physical models, thermodynamics offers a powerful framework for understanding the energetic and probabilistic nature of thought, behavior, and well-being.

Thermodynamics and the Irreversible Self

The first law of thermodynamics tells us that energy cannot be created or destroyed, only transformed. Each decision you make, even the smallest one, is an energy exchange. Choosing to grab a coffee before leaving the house burns mental and physical energy, shifts your timeline, alters your position in traffic, and repositions you in the network of human interaction for the day. That energetic shift becomes part of the causal fabric of your life. You can’t undo it; you can only interact with what follows.

More importantly, the second law of thermodynamics introduces entropy, a concept that is key to DEIT. Entropy is the natural tendency of systems to become more disordered over time. In practice, this means that the consequences of a decision, once released, spread, morph, and ripple outward in increasingly complex and unpredictable ways. You can’t “reverse” a decision any more than you can un-crack an egg or un-drop a match into a forest. The resulting cascade of events from even one seemingly minor choice becomes so entangled in your timeline that it defies reconstruction.

Take this simple example: You leave home 90 seconds late because you checked if you locked the door. As a result, you hit different traffic, avoid an accident, take a different route, arrive at work later, and interact with different people at different moments. You may never know what you avoided or what was set into motion. That one decision, like a small shift in temperature in a weather system, becomes thermodynamic fuel for a chain of alterations that are irreversible, incalculable, and often invisible.

And just like in physics, the third law of thermodynamics reminds us that reaching a state of zero entropy, perfect order, is not possible. The fantasy of editing one choice from our past and surgically replacing it with a better outcome is just that, a fantasy. Any change, no matter how small, reshapes not just the next step but the entire energetic system of our life. Regret imagines precision in a world governed by entropy. The scientific reality tells us otherwise.

Chaos Theory and the Butterfly in Your Coffee Cup

If thermodynamics reveals the irreversibility of decision-making, chaos theory shows us its unpredictability. Popularized by meteorologist Edward Lorenz in the 1960s, chaos theory emerged from attempts to model weather patterns.⁴ Lorenz famously discovered that rounding a large number slightly in his model led to drastically different outcomes; a phenomenon he termed “sensitive dependence on initial conditions,” or more popularly, the butterfly effect. The metaphor is powerful: a butterfly flaps its wings in Brazil, and a tornado forms in Texas. 

The lesson? In complex systems, even slight input changes can yield massive, nonlinear outcomes. Human life, with its infinite social, emotional, and environmental variables, is one such chaotic system; an adaptation I refer to as the psychosocial butterfly effect.

Consider this: You stop for coffee on your way to work. That pause changes your route by one street. Because of that, you hit a red light and miss a serious accident by 30 seconds. You might see someone from your past. Or you arrive at a meeting slightly flustered, which affects your tone, shifts how your ideas are received, and changes your career path. Even small choices can reshape our lives, sometimes on a minor scale and at other times, a matter of life and death. We can't always tell which choices matter.

In chaotic systems, you can’t trace back through the noise to see exactly how you got here. More critically, you can’t predict what would have happened if you’d chosen differently. This renders regret not only emotionally harmful but mathematically irrational. There’s no reliable line from "If I had done X" to "Y would’ve happened," only the unknowable possibilities of what might have been.

To put this into perspective, if you consider just 40 binary decisions you've made—each with a yes/no or stay/go outcome, that results in over a trillion potential life paths (2⁴⁰ = ~1.1 trillion). Selecting the one that would have led to a "better" life assumes not only perfect foresight but perfect knowledge of all downstream interactions, which is statistically and practically impossible. The odds of correctly forecasting how a single different choice would have unfolded, let alone ensuring it leads to improvement, are staggeringly low. You're 3,700 times more likely to win the Powerball jackpot than to predict a better life path from one alternate decision.

Even more compelling is how chaos theory reveals fractals and feedback loops in our decision-making.⁵ Patterns in how we act, such as avoidance, impulsivity, and risk-taking, replicate over time, scaling up to shape our engagement with life. These behavioral patterns are not isolated; they feed into future choices, just as past decisions influence them. In a chaotic system, each choice is part of a fractal web. Change one node, and the pattern remakes itself.

Quantum Mechanics and the Collapse of Possibility

If thermodynamics and chaos theory challenge the physical and mathematical foundations of regret, quantum mechanics targets its metaphysical assumptions. In the quantum world, the realm of subatomic particles and wave functions, certainty itself breaks down. And that collapse of certainty perfectly mirrors the failure of regret.

According to Heisenberg’s Uncertainty Principle, the more precisely we know a particle’s position, the less we can know about its momentum, and vice versa.⁶ The very act of observation changes what’s being measured. Translating that into human terms: the more we fixate on a specific outcome we think we missed, the less clearly we see the full system that created it. Our imagined alternative timeline becomes a distortion, not a clarity.

Then there’s quantum superposition, the idea that particles exist in all possible states until observed, at which point they “collapse” into one outcome. Human decisions behave similarly. Before we act, countless future paths are theoretically possible. But once we make a choice, our life becomes a single entity. The other options cease to exist. They are no longer accessible. They’re not tucked away in some drawer we can reopen. They’re gone. Regret, then, is a longing for superpositions that no longer exist. It’s trying to re-collapse a wave function into a different outcome, something both quantum physics and human psychology tell us cannot be done.

Even more fascinating is the quantum concept of entanglement, where two particles, once connected, can affect each other instantaneously across space. In life, we are entangled with others: our choices affect theirs, theirs affect ours. Every decision alters the fabric of not just our timeline, but those of the people around us. The notion that we can change one decision in isolation and keep everything else intact, such as our relationships, our identity, and the people we’ve become, is a quantum absurdity.

In this sense, quantum theory offers more than a metaphor for the Decisional Entropy Illusion. At the most fundamental level, nature does not support the idea that alternate choices would have reliably yielded better outcomes. The collapse is real. The alternatives were never real in the first place.

Systems Thinking and the Web We Cannot Untangle

Moving from particles and probabilities to systems theory, the science of interdependence shows that nothing exists in isolation. Each part affects and is affected by others. Life, too, is a dynamic system full of feedback loops. Consider regretting a job offer you declined five years ago. At first, it feels like a missed chance for more pay or prestige. But systems thinking asks: What else would have shifted? Would you have lost touch with people essential to your life? Missed an opportunity to support a loved one or a challenge that shaped your growth?

From this perspective, systems theory encourages us to focus not on a single decision, but on the ripple effects. Like ecosystems, interventions yield emergent outcomes, realities unpredictable from isolated parts. Your career, relationships, and self-concept are shaped by the interaction of many factors. To change one shifts them all. Regret imagines changes without consequences. But systems, and lives, don’t work that way.

Unintended Consequences and the Illusion of Control

From systems theory, we turn to the Law of Unintended Consequences, a principle born in sociology and economics but deeply applicable to our everyday choices.⁷ It warns us: even well-intentioned actions in complex systems can have unforeseen outcomes that often run counter to our goals.

When we regret the path not taken, we typically imagine only the best-case outcome of that alternate choice: the dream job brings fulfillment, the unspoken words resolve conflict, and the missed opportunity becomes success. In reality, each alternate timeline faces the same chaos, entropy, and complexity. That city you didn’t move to may have brought financial strain. That job could have ended during a recession. That idealized relationship might have turned toxic.

The law of unintended consequences reminds us that even minor changes unleash ripple effects we cannot predict. When we imagine a “better outcome” from a different past, we are writing a story with the benefit of hindsight where none of the unknowns that would have come with it.

Evolutionary Path Dependence and the Self You Can’t Unbuild

In evolutionary biology and economics, the concept of path dependence explains how certain developments become “locked in” due to historical choices and events.⁸ Once a river carves a channel, the water follows it. Once a species evolves a trait, subsequent evolution builds upon it. Changing course becomes harder and sometimes impossible.

Human development follows a similar trajectory. Your beliefs, habits, and personality traits are not the result of isolated choices, but rather the accumulation of layers of experience. Regret imagines building a better self with different choices, but life doesn’t offer clean restarts. The degree you pursued, the people you dated, the places you lived in, the restaurants you dined at, and the times you were early or late all shaped your lens on the world.

Imagine regretting your college major. You wish you had chosen something more practical. But in that regret, you miss the friends you made, the mentors who guided you, and how art or philosophy sparked your creativity. Change the major, and you don’t just change your job. You change your path and maybe even the person you are. Path dependence teaches us: we are not products of perfect design, but of accumulated adaptations. To regret the path is, in a way, to regret the self. And that serves no one.

The Bayesian Brain and the Illusion of Perfect Decisions

Modern neuroscience suggests the brain is not a perfect decision-maker but a prediction engine, always making the best possible choice with the information available at the time. The Bayesian brain hypothesis suggests that we constantly update our internal model, yet every decision remains uncertain.⁹ Regret distorts this reality, creating the mistaken belief that we should have known better when, in truth, we never have perfect knowledge. Hindsight bias then deepens this illusion, making better alternatives seem clear only in retrospect.

In biological systems, feedback loops maintain balance and promote adaptation. When we respond to setbacks with healthy reflection, we adjust future behavior. But regret often traps us in a dysfunctional loop of reliving the same emotional discomfort without resolution. This kind of rumination disrupts emotional regulation and impairs our ability to make new, clear-headed decisions. Instead of learning, we spiral. Regret, then, becomes a feedback error similar to a thermostat overheating a room because it can’t read the current temperature.

Limited Bandwidth, Cognitive Load and Information Theory

Our brains face hard limitations. Cognitive Load Theory reminds us that working memory is limited in capacity.¹⁰ Under stress or complexity, this bandwidth shrinks further. We are not built to evaluate every variable or predict every outcome. The brain often satisfices, choosing “good enough” options, not out of laziness, but necessity. Regret assumes we could have made the best choice when the brain is doing its best with limited processing power.

These constraints connect directly to concepts from information theory. Claude Shannon’s foundational work demonstrated that reducing uncertainty in any system requires energy.¹¹ In essence, clarity is costly. To fully know the outcome of every alternative decision would demand an impossible amount of informational and metabolic resources. Nature doesn’t operate that way, and neither do we.

Ultimately, the brain’s purpose is to anticipate the future. It refines predictions based on error, not to dwell in them, but to adjust course. Obsessing over what cannot be changed diverts attention from what can. Regret, therefore, competes with the brain’s essential function: forward-thinking adaptation.

Taken together, these scientific models present a central argument: the experience of regret is based on an inaccurate assessment of the brain's capabilities. Alternate pasts are fundamentally unknowable, not just inaccessible, because the brain can never operate with perfect information. Regret is thus not only unproductive but fundamentally at odds with how the mind, and real systems, are built.

The One Truth Left Standing

From physics and chaos theory to psychology and network science, the message is consistent: regret is incompatible with the operation of complex systems. The Decisional Entropy Illusion Theory explains that you cannot simply “change a decision” in your past and expect to retain the life you now have, minus the pain. The moment has passed. The energy has dissipated. The path has been walked. The wave function has collapsed.

And yet, this is not a fatalistic argument. It is a liberating one. If you cannot rewrite the past, you are empowered to shape the future. Use science not as an excuse to linger in the past, but as a call: move forward, invest your energy purposefully, and make your next choice count.

Scientific Metaphors as Conceptual Tools

This article uses ideas from thermodynamics, quantum mechanics, and chaos theory as metaphors rather than direct explanations for how people think and feel. These scientific rules appear at different levels of reality, but their features, such as one-way changes, unpredictability, and chance, serve as useful comparisons to help us understand how regret works. These metaphors are not just images; they serve as bridges that link psychology with basic science, creating new ways of thinking and new questions to explore. Importantly, these comparisons can help people cope. For those who struggle with regret, seeing their feelings through science may give comfort and a new perspective. It helps to view regret not as a personal failure, but as a normal part of life in a world that is uncertain, low on energy, and connected in many ways.

When Regret Has a Role

Even as we dismantle the illusion of regret, it’s important to acknowledge that regret, while scientifically flawed, can still serve a purpose. It helps us clarify our values. It teaches us about who we were and who we want to become. It sometimes acts as a moral compass for future action.

But to be useful, regret must be transmuted. It must evolve from a fixation on the past into a compass for the future. Left unchecked, it becomes a trap that can lead to depression, low self-esteem, and anxiety. But understood through the lens of science, it becomes a tool: not for rewriting history, but for writing what comes next. A fundamental insight about your decisions thus far in life is that you are still in existence, with the opportunity to continue making more decisions moving forward; a fact that not everyone has had and that should not be taken for granted.

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