Thinking critically

Some of our beliefs come from logical conclusions that we make about the world around us. This often involves first-hand information (our own observations), but it can also include information from external authorities that we evaluate with critical thinking. This process involves analysis, testing, self-correction, and formulating a conclusion -- hopefully with an understanding that there may be unknown unknowns (i.e., leaving room for future correction).

The Scientific Method is probably the the best real-world application of critical thinking. (Unfortunately, science can be corrupted by money and other forms of scientific bias, giving faulty evidence, manipulated statistics and pseudoscience dressed up as real science.)