A specialization of field of study. Each instance of scientific discipline is a specialized body of knowledge, theory, hypotheses, observations, and problems, which together constitute the informational content of a systematic endeavor to explain (some part of) the natural world by rational (and frequently, quantifiable) methods, including, but not limited to, induction, falsifiable hypotheses tested by repeatable physical experiments, and deductive proof. Instances of scientific discipline include the traditional hard sciences (e.g., physics, chemistry), the life sciences (e.g., life science, genetics, toxicology), and mathematics.