In ancient Greece, philosophers and thinkers invented a process for arriving at truths about the world that we know today as deduction. These processes relied on taking general statements about the world and applying various logical rules to them in order to answer particular questions.
Deduction was enormously useful, especially in mathematics. It is deductive reasoning that led to the Pythagorean equation, a general statement that works with every right triangle you will ever encounter.
Deduction had weaknesses, however, because it could give you answers that did not fit your observations. That was what drove the seventeenth-century English philosopher Francis Bacon to popularize a new way of organizing thought: induction.
Inductive reasoning takes deduction and flips it around. Instead of inventing axioms and applying them to specific observations, induction worked by collecting numerous observations and then deriving general principles from the amassed observations.
Bacon’s empirical approach was a great leap forward for the study of the natural sciences by giving precedence to observations over theories. If you collected 100 observations and 99 of them could not be explained with your current theory, the theory would have to be changed.
The modern scientific method is dependent upon inductive reasoning. However, Bacon himself warned against equating the two. Induction is only half of science. Eventually, enough observations have been collected to develop a strong theory, such as the theory of gravity.
At that point, the theory becomes the standard for future observations. Our observation of a heavier-than-air jet does not lead us to conclude that gravity is being violated – we know that the plane is in fact operating according to the rules of gravity. We also assume those rules are consistent, or else we could never be sure if the next jet would get off the ground.
Induction is incredibly versatile, and it encourages a healthy skepticism about statements that can’t be verified by facts. If used properly, this form of reasoning is one of the best ways to align your ideas and beliefs with empirical reality.