What was herbert spencers idea of survival of fittest?

Herbert Spencer's idea of "survival of the fittest" refers to the concept that individuals or groups best adapted to their environment are more likely to survive and reproduce. He applied this idea to social and economic contexts, suggesting that competition among individuals in society would lead to social progress. Spencer's views were foundational to social Darwinism, which often misapplied biological concepts to justify social inequalities. His perspective emphasized the importance of adaptation and competition in both nature and human society.