First, let's review by watching this video:
To effectively perform critical thinking, you need to understand LOGIC.
Logic is reasoning conducted or assessed according to strict principles of validity. In other words, it needs to be valid (true) and factual. There are different forms of Logic but to simplify, let us analyze three. These three forms of Logic are: Deductive Reasoning (Arguments), Abductive Reasoning (Arguments), and Inductive Reasoning (Arguments).
Deductive Reasoning: The process of reasoning from one or more statements (premises) to reach a logical conclusion [1]. If all premises are true, the terms are clear, and the rules of deductive logic are followed, then the conclusion reached is necessarily true. Let us examine
Premise:
All humans are mortals
Mr. A is a human
Conclusion: Mr. A is mortal
It is an absolute truth to believe that all humans are mortals (unless you believe in Vampires or Zombies as being humans) and the fact that Mr. A is a human. Therefore, the conclusion must be true.
Abductive Reasoning: is a form of logical inference (hypothesis); observation or set of observations and then seeks to find the simplest and most likely conclusion from the observations. Abductive predictions will have a remnant of uncertainty or doubt, which is expressed in retreat terms such as "best available" or "most likely". This is the most common form of critical thinking but not the best form because there will always be some doubt. This is used in law, the medical field, and most of your lives.
Premise:
Most classical music composers love the Opera
Cardi-B is a hip-hop artist
Conclusion: Cardi-B doesn't love the opera
Although premise 1 and 2 is factual, the third doesn't necessarily mean its true. For all you know, she may secretly love the Opera and just doesn't talk about it. Therefore, doubt can creep into your mind.
Inductive Reasoning: A method of reasoning where one's experiences and observations (specific evidence), are synthesized to come up with a general truths.
Premise:
Johnny cheated on me with another person
Johnny was a man
Conclusion: All men are cheaters!
Based on this personal experience/evidence, the conclusion is created for the whole. We can even say the same thing about racism, politics, and parents... does your personal experience dictate the general truth of the whole?
References:
[1] Sternberg, R. J. (2009). Cognitive Psychology. Belmont, CA: Wadsworth. pp. 578. ISBN 978-0-495-50629-4.