Deterministic Nihilism and the Biological Untruth of Human Existence

Nietzsche once declaimed that when one affirms even an infinitesimally small moment of existence, they simultaneously affirm the entirety of it. Why precisely is it then, that the converse is not necessarily as true? Why does a singular transgression, or ethical lapse, not cast upon an unending veil of moral catastrophe? Why does a singular instance of meaninglessness, not translate into an inexorable, overarching nihilism? Why is it that the default of an Existentialist position is to invoke subjective meaning, as opposed to furthering the cause of objective meaninglessness?

Whilst it is not oftentimes recognized, there exists a critical aspersion cast in light of all human traits heralded in transcendence or divinity - be they a function of principle, sentience or mortality. When asked to concretely describe free will or love, in the context of human existence, how might one respond? Empirically, in a fashion adherent to epiphenomenalism, the determination of every single human behavior can be made attributable to a biological inevitability. Serotonin and Oxytocin dictate one's psychological health and sociability. Genetic asymmetries, abnormalities and patterns manifest in the form of one's physiology. Neurological biochemistry is effectively responsible for the totality of one's thoughts, sentiments and interactions. Relationships are predicated on an ineradicable series of Darwinian constructs. Whether an individual lives or succumbs to a medical affliction, is almost invariably a consequence of factors intractable to his/her influence. Which constituent or dimension of human existence is not predetermined by a truth exogenous to their apparent 'will'?

If one were to accept the propositions implied above, every element of human interaction that isn't solely empirical is likely to be remodeled into satisfying precisely an empirical metric. Sacrificial and valorous acts of morality may then be considered a consequence of guilt avoidance, designed to reinforce a palatable neurochemical state. Benevolence and kin selection suffer the same argumentative fate. Likewise, 'love' shall constitute a prerequisite to a species-wide mechanism, as opposed to a miraculous confluence of personalities.

This isn't even a stance constructed at an elementary threshold of physical existence, such as one akin to Laplace's prefacing thoughts on the predetermination associated with subatomic particles, or contemporaneous accounts of Quantum-Mechanical Time Evolution and Unitarity. Instead, one can derive it merely by virtue of observing the abject and irremediable frailty of the human condition.

Life is not lived. It is witnessed by the recipient of its fate.