The simplest explanation of critical thinking is that it is your thoughts plus truth. If you take nothing else away from this book, the importance of facts and logic cannot be stressed enough. The most crucial thing you can do to develop as a critical thinker is to support what you think, say, and do with facts, and subject it to logical scrutiny.
As stated earlier, critical thinking is the ability to analyze facts in order to reach a conclusion logically. A fact is a statement that can be supported by external evidence or observable experience. Facts are certain, and they are true. Elementary, you say? Maybe the definition is simple but applying it has been the subject of philosophers and scientists for centuries.
We’ll talk more about facts later, but for now let’s just say that it is something that we know to be true, whether it is because we observed a certain action, scientists tested a physical principle in a lab, historians have used rigorous methods to ascertain its existence, etc. Facts are the bricks that make up critical thought.
Logic is the mortar binding the facts together. Logic is simply the set of rules and relationships governing claims about the truth and falsity of statements. In plain English, logic lets us determine when we can say two different statements lead to a new statement. The classic example in freshman philosophy classes is “All men are mortal. Socrates is a man. Therefore, Socrates is a mortal man.” It sounds basic both since all of us have already internalized some level of logical thinking, and because this common sense statement disguises an abstract law of logic.
In this argument, the premises, or the starting points established as true for the sake of discussion, do allow us to make a new statement. We also know that we cannot say “All mortals are men” because our experience shows that there are mortals who are not men.
In this case, logic doesn’t allow us to make the statement “All mortals are men.” It does not follow from the premises, and it creates an invalid relationship according to other rules of logic. Logic prevents us from making contradictory statements, from saying things that simply do not make literal sense.
A defendant’s alibi is a simple example of logic preventing invalid conclusions. If we know that the accused was in a different place during the actual crime, we dismiss the case because we also know that a person cannot be in two places at the same time. It’s also why we tend to be suspicious of politicians who make contradictory claims—you can either want to do something when you’re in the office or not want to do it. Saying two different things is not only confusing when it comes to predicting the candidate’s policies, but it is also logically invalid.
Logic lets us gather facts into new insights, rather than letting facts simply exist like so many pieces of a broken puzzle. Conversely, facts make logic have real consequences, rather than simply remaining abstract figures on paper. Facts and logic are the foundation for critical thinking, so get into the habit of identifying the facts and logic behind the statements and attitudes around you, including your own.
You may find considerable gaps in this area, allowing you to question things and present new ideas, or you might be able to reinforce those statements with facts and logic. The point is that in critical thinking, supporting our statements is as important as making them in the first place, and there are specific ways we should be supporting those statements.