Tenacity

Accepting ideas as valid simply because those ideas have been accepted for so long.

Intuition

Accepting ideas as valid because they "feel" right.

Problems: 1) Hindsight Bias: the tendency to believe, after learning the outcome of something, that we "knew it all along".

2) Overconfidence: the tendency to overestimate the accuracy of our beliefs.

3) Confirmation Bias: the tendency to search for & consider only things that support what you already believe.

Authority

Accepting ideas as valid because an authority figure says they are true.

Rationalism

A process which uses existing ideas and the principles of logic to develop new valid ideas.

Problem: Sometimes the existing ideas are invalid.

Empiricism

Gaining knowledge by observing events.

Science

A process that combines rationalism and empiricism.

Rationalism is needed to develop a theory.

Empiricism is needed to test the validity of the theory.