Everyone must have a rational, well-thought-out approach to solving problems. Common sense and critical thinking both play a role in problem solving, as well as how people regard life, situations and each other. Common sense and critical thinking, however, differ in their approach and level of operation.
Common sense, as defined by the Plus Root website, is innate rational thinking that occurs organically in rational humans. Common sense involves thinking and problem-solving skills developed from intuition, natural logic and the human ability to observe events and absorb information and lessons from them. These observations allow you to learn from experience and thus to hone and implement sound judgment. You use common sense to approach and attempt to solve problems in day-to-day life. Every human being gains and uses common sense to apply impartial, unbiased and responsible logical decisions
Critical thinking occurs when a person deliberately examines a situation based on his own knowledge and philosophies. Critical thinking involves judging a situation based on studied reasoning, where the person intentionally and consciously focuses on a subject. The quality of critical thinking is based on how sound the eventual judgment of a situation is. Critical thinking allows for planning, calculating, investigating and explaining; you use it for situations that require a larger degree of concentration and deliberation.
Common sense is, by definition, a sound conclusion. Critical thinking, on the other hand, can be either sound or unsound. Mistakes in logic can be made through critical thinking. Critics are not always right, and their conclusions can be colored by their own prejudices.
Another point of difference lies in the levels of awareness at which both consciousness and critical thinking operate. Critical thinking always occurs at a conscious level, whereas common sense occurs on a liminal level of thought, which the Plus Roots website calls "a workaday consciousness."
Although critical thinking and common sense require different levels of awareness and consciousness to operate, both methods are rational in their arguments (or, at the least, attempts to be rational). Both must adhere to some logical form and logical requirements.