This document discusses the nature and theories of intelligence. It defines intelligence as one's ability to comprehend their environment and think rationally. Theories discussed include identifying different types of intelligence like verbal, mathematical, spatial abilities. Intelligence is thought to be a combination of inherited ability (nature) and environmental influences (nurture). Intelligence tests aim to measure intelligence through standardized tests, but they may reflect cultural biases and only demonstrate performance, not true competence. Intelligence tests are commonly used in educational and employment screening.