Becoming a logical person is not a matter of memorizing and applying formulas, or just learning how to tell the difference between a valid and an invalid syllogism. Rather, it involves cultivating intellectual habits and skills that, though they may seem simple and obvious, are only achieved after years of struggle and education.
In his book “
Being Logical: A Guide to Good Thinking,” venerable philosophy professor D.Q. McInerny lays out the following 10 habits that people must cultivate if they are to think clearly and effectively:
1) They’re Attentive
“Many mistakes in reasoning are explained by the fact that we are not paying sufficient attention to the situation in which we find ourselves,” writes McInerny. The logical person has thus trained himself to always pay attention to the details—even in situations that are familiar—lest he make a careless judgment.
2) They Get the Facts Straight
“If a given fact is an actually existing thing to which we have access, then the surest way to establish its factualness is to put ourselves in its presence. We then have direct evidence of it. If we cannot establish factualness by direct evidence, we must rigorously test the authenticity and reliability of whatever indirect evidence we appeal to so that, on the basis of that evidence, we can confidently establish the factualness of the thing.”
3) They Ensure That Their Ideas Are Clear
Our ideas are the means by which our minds understand the objective world. Clear ideas faithfully reflect that world, whereas unclear ideas give us a distorted view of the world. The logical person is constantly testing his ideas to make sure they accurately depict their objects.
4) They’re Mindful of the Origins of Ideas
The logical person knows which of his ideas are based on things that actually exist in the world. He knows, for instance, that his idea of “cat” corresponds to things in the objective world known as “cats.” As a counterexample, there are a lot of people who have an idea that there existed a female pope named Joan in the 9th century. But if they spent time looking into the source of that idea, they would find that it’s widely regarded by respectable historians to have originated in legend.
5) They Match Ideas to Facts
McInerny writes, “To prevent my idea from being a product of pure subjectivism, in which case it could not be communicated to others, I must continuously touch base with those many facts in the objective world from which the idea was born.” This is easy to do with ideas that have a simple correspondence to things in the world outside our minds (e.g. my idea of “cat” refers to an actual cat). It’s much harder to do, as we’ve all experienced, with more complex ideas such as capitalism and socialism, or conservatism and liberalism. For these ideas to remain sound, they must constantly be linked to, and supported by, facts that are accessible to all.
6) They Match Words to Ideas
We can only communicate our ideas to others if we use words that accurately convey those ideas. But finding the right words can be difficult. When difficulty arises, we should go back to the sources:
