Question

What theory argued that humans and society improved through competition and survival of the fittest?

Answer 1

Social Darwinism. It was a late-19th‑century theory (associated with thinkers like Herbert Spencer) that applied Darwinian ideas — “survival of the fittest” and competition — to human society, arguing that social progress came from competition and the success of the "fittest." It’s now widely criticized as a misapplication of biological evolution and was used historically to justify laissez-faire economics, imperialism, and eugenics.