Physicalist Deconstruction of Existentialism: Neurobiological Limits of Freedom and a Critique of Sartre

In his work Existentialism Is a Humanism, Jean-Paul Sartre proposed a thesis that represents the pinnacle of philosophical arrogance: "The coward makes himself cowardly." From the perspective of modern science, this assertion is not merely outdated—it is a cognitive anachronism built upon a total disregard for biological reality. The Straw Man of Existentialism Sartre deliberately substitutes concepts, creating a "straw man" based on a false premise. He judges individuals existing in fundamentally different physical realities by a single standard. When he claims that the "wicked," the "frail," or the "lazy" became so by their own will, he denies the human being’s status as a living system. In biology, there is no such thing as "laziness"—there is only a low level of dopamine or an energy-saving mode of mitochondria. Sartre attempts to impose "will" where electrochemical cascades are at play. Biological Disability: The Coward or the Hostage of the System? Sartre accuses the coward of "choosing" to hide rather than fight. Let us analyze this through the lens of physicalism. Consider two people at a moment of danger: The first has a high activation threshold in the amygdala and an effective release of norepinephrine. Their brain is primed for combat; their vessels are dilated. Their "choice" to fight is merely the execution of a program already prepared by the body. The second possesses a pathological reactivity of the limbic system. They experience an instantaneous vascular spasm, a surge of cortisol, and the total paralysis of the prefrontal cortex. This person does not "choose" cowardice—they become disabled by the moment. In a state of cortisol shock, a person is physically incapable of cognizing the situation. Their prefrontal cortex—the substrate of "will"—is de-energized. To demand a free choice from such an individual is equivalent to judging a paralyzed person for failing to stand and walk. Sartre intends to label a biological breakdown as an "existential choice," which is an act of sophisticated cruelty. Man as a System, Not a Sum of Actions Sartre asserts a triviality: that a man is nothing but the sum of his actions. This is a fallacy. A human being is the sum of their atoms, neurons, mitochondria, and their entire biochemical system. Actions are merely the interface through which this system interacts with being. A deceased person remains a human being (a physical system) for a time, even though their "sum of actions" has concluded. Sartre ignores physiology, attempting to blame the mechanism for its blown fuses. His teaching is a dark pit of anti-science, where the "guilt" of the coward is attributed to their biological architecture. Conclusion It is time to acknowledge that the old philosophy has shattered against the rock of physicalism. Cowardice is not a moral defect; it is a physical failure of the brain's "top-down control." We are self-regulating matter, and our freedom ends where the chemistry of stress begins. Sartrean existentialism is a cruel fairy tale that punishes a human being for the limits of their hardware (biological durability). In modern science, the place for such a philosophy is in the archives of delusions.