Antagonistic Pleiotropy
A gene can have effects that differ across traits or stages of life.
The Mechanism: Antagonistic pleiotropy describes cases where a genetic variant has beneficial effects on one trait or life stage and harmful effects on another. It is one evolutionary hypothesis for aspects of aging, not a rule that every gene helps early and harms late.
The Philosophical Pivot: Biological costs can be delayed, making a trait look purely beneficial until a different stage of life. The organism exists across time, but selection pressures may not value every stage equally.
The Horizon: The idea helps explain why evolutionary history does not produce perfect designs. It can guide research into aging, though the biology involves many genes, environments, and processes.
A theory of aging is not a verdict that decline is inevitable or that treatment is pointless. It explains constraints that medicine may study and sometimes alter.
A benefit at one moment can cast a cost into the future without either moment being the whole story.
Evolution can preserve a bargain whose cost arrives later.
Which advantages in my life today might be borrowing from a future I have not yet considered?