A logician is a person who studies or practices logic, which is the systematic study of valid reasoning and argumentation. They analyze the structure of arguments, identify fallacies, and develop principles that help in understanding how conclusions can be drawn from premises. Logicians often work in fields such as philosophy, mathematics, and computer science, where clear reasoning is essential. In addition to theoretical work, logicians may also apply their skills in practical areas like artificial intelligence and linguistics. Their expertise helps in creating algorithms and understanding language structures, contributing to advancements in technology and cognitive science. Related figures include Aristotle, known for his foundational work in logic, and Gottlob Frege, who significantly advanced modern logic.