How did Thomas Henry Huxley’s view of natural selection differ from Charles Darwin’s?

While Thomas Henry Huxley is famously known as "Darwin’s bulldog" for his vigorous public defense of Charles Darwin’s work, his initial scientific perspective on natural selection differed from Darwin’s.1

Huxley initially struggled to accept natural selection as the primary mechanism for evolution. Instead, he favored a theory involving an internal source of variation that could produce new species "at a stroke," rather than through the gradual process proposed by Darwin.1

Despite this early disagreement, Huxley championed Darwin’s broader naturalistic approach. He viewed it as a powerful tool to establish an independent scientific elite and to challenge the influence of religious institutions in public life. While he remained skeptical of the specific mechanism of natural selection for a time, he utilized Darwin’s Origin of Species as a central weapon in his campaign to promote scientific naturalism and secularize the debate over human origins.1