What Is the Difference Between Proof & Evidence in Science?

Evidence

• According to the Merriam-Webster dictionary, science is "knowledge or a system of knowledge covering general truths or the operation of general laws, especially as obtained and tested through scientific method." The core of the scientific method is using evidence to test theories. Evidence is specific observations of a given phenomenon. Galileo, the famed Italian scientist, was reputed to have collected evidence on gravitational forces by dropping balls from the top of the Tower of Pisa, timing how long they took to hit the ground. By analyzing this evidence, Galileo discovered that, disregarding air resistance, all objects accelerate at the same rate when falling. Galileo's experiment is a model example of the scientific method where theory is derived from observational evidence.

Proof

• Proof exists when you can say that a statement or theory is absolutely true in all instances. Proof is a concept that is really only applicable in mathematics, because math deals with abstract concepts and definitions. The statement 1+1=2 is a true statement and will always remain true because the definitions of 1 and 2 never change. Definition statements and logic are used to create theorems, which are absolutely true or false.

Theories vs. Theorems

• Scientists collect evidence and from there form theories. Every theory in science is falsifiable; that is, if new evidence surfaces that does not com+port with a current theory, then the theory needs revision. A scientist may then develop a new theory that addresses the old body of evidence as well as the new outlier data. Theorems, on the other hand, state unchanging mathematical laws. A proof is the attempt to use logic to verify these laws. The term "proof" is now understood as some fact that absolutely affirms a theory or idea.

Blurring Lines

• It's dangerous to blur the lines between proof and evidence in scientific discussion. Particularly in popular culture, people hear about scientific studies and think that they prove one position or another. Such a fundamental misunderstanding of the essence of science is detrimental to society because people stop questioning old theories because they think they have already been proved, which leads to intellectual stagnation.