Ethical Realism

March 6, 2013

Why Logic is Important

Filed under: epistemology,philosophy — JW Gray @ 5:56 am
Tags: , ,

Recommended reading: What is Logic?

Why is logic education important? The main question here is what the real point of logic education is. The real point of logic is not to teach people how to be logic professors, or to increase test scores, or to impress potential employers. Philosophers and mathematicians were very interested in understanding logic long before it was taught in universities precisely because of how important it is. Why is logic so important? The answer is that logic helps us better understand good arguments—it helps us differentiate between good and bad reasons to believe something. We should want to have well-justified beliefs. We want to know what we should believe. Understanding good argumentation helps us understand when we should believe something, and understanding logic helps us understand good argumentation.

How exactly does logic help us understand good argumentation? There are many necessary characteristics that good arguments must have, and logic tells us what some of those characteristics are. Logic also helps us better understand concepts that are relevant to good argumentation.

What is a good argument?

Good arguments are good reasons to believe something is likely true. If we know of a good argument to believe something, then we should believe it. For example:

  1. All dogs are mammals.
  2. If all dogs are mammals, then all dogs are living organisms.
  3. Therefore, all dogs are living organisms.

People should agree that “all dogs are living organisms.” We know the premises are true (that “all dogs are mammals” and “if all dogs are mammals, then all dogs are living organisms”). We know that if the premises are true, then the conclusion has to be true as well. The premises can’t be true and the conclusion false at the same time because the argument is logically valid.

What characteristics do good arguments have?

Ultimately good arguments must have sufficiently justified premises, and the premises should be appropriately relevant to the conclusion. Even so, there is much to be said about this criteria. Many of the necessary characteristics of good arguments are covered by the various issues discussed in logic classes—logical form, logical validity, the distinction between inductive and deductive reasoning, argument interpretation, and informal fallacies. Examples about what various general logical issues can teach us about good argumentation includes the following:

  1. Logical form – Understanding logical form is of paramount importance to understanding good deductive argumentation, but ordinary language makes it very difficult to discuss logical form. It is much easier to understand logical form and how it relates to good argumentation after learning about logical form in a logic class. For example, “If Socrates is a man, then he is mortal” has the logical form “If A, then B.”
  2. Logical validity – Logically valid deductive arguments have premises that guarantee the truth of the conclusion (assuming they are true). An invalid deductive argument gives us no reason to think the conclusion is true. In that case the premises can be true and the conclusion can be false at the same time.
  3. The distinction between inductive and deductive reasoning – All good deductive arguments are logically valid, but good inductive arguments aren’t. Inductive arguments are not meant to be valid because the premises are only supposed to make the conclusion probable. A good inductive argument is unlikely to have true premises and a false conclusion, but it can happen. For example, the evidence scientists use to support scientific theories is inductive and it is possible that the theories are actually false (imperfectly accurate). The predictions made by scientists could always turn out to be false, but they are likely to be true when they are well-justified. Even dropped objects could fail to fall in the future. Even so, we should agree that dropped objects will fall in the future anyway.
  4. Argument interpretation – It is important to fully understand people’s arguments and to know how to clarify their arguments. It’s important that we know what exactly the premises and conclusions are. Sometimes understanding an argument also requires us to identify unstated assumptions and some creativity could be required. It is impossible to properly debate with someone who doesn’t understand your arguments. An argument can’t be properly refuted unless it is understood well.
  5. Informal fallacies – Informal fallacies are errors in reasoning other than having an invalid argument form. Interpreting arguments uncharitably is one common example called the “straw man fallacy.”

There are innumerable specific examples about how each general issue can apply to good argumentation. One example is that people often refute the conclusion of an argument by arguing against a premise. However, it is possible for a different argument to be given for any given conclusion. Refuting a premise of an argument does not simultaneously refute the conclusion. Consider the following argument:

  1. If the President of the United States is a lizard, then the President is a mammal.
  2. The President is a lizard.
  3. Therefore, the President is a mammal.

In this case both premises are false, but the conclusion is true. Stating that the premises are false gives us no reason to think the conclusion is false. Such an argument could look like the following:

  1. “The President is a lizard” is false.
  2. Therefore, we should reject that “the President is a mammal.”

This argument is clearly invalid. The premise is true, but the conclusion is false. This example shows how understanding validity can help us understand why certain arguments fail to be good arguments. Actual people do argue this way now and then, so learning about it in a logic class could actually help people come to a realization that they might not think about otherwise.

Many examples were given concerning how logic classes can help us better understand good argumentation. However, there are potentially other characteristics of good arguments that are not discussed in logic classes. The philosophical domain called “epistemology” concerns the nature of knowledge, rationality, and justified belief. There are certain details about what counts as sufficient justification and rational thought that logic does not cover, but is covered by epistemology instead. Epistemology is the domain concerning how open-minded we should be to avoid being close-minded, how skeptical we should be to avoid being gullible, and how much evidence a belief requires in order to be sufficiently justified. Also, logicians don’t tell us if any beliefs are self-evident, if intuition is ever a good reason to believe something, or when we can rationally assume a premise to be true without argument. Those are issues concerning epistemology.

Why is good argumentation important?

Logic alone can’t tell us why good argumentation is important. It’s a philosophical question. Answers include the following:

  1. We want to know what’s true. Good arguments can tell us what is likely true.
  2. We often can’t believe what we should believe unless we understand good augmentation. Understanding good argumentation helps us know what we should believe, and it helps us prove to other people what they should believe. Moreover, we should believe certain things because we know about good arguments. Believing what is true at random is not appropriate. We should believe what is likely true based on a good reasoning process.
  3. Our beliefs can motivate us to behave in certain ways, and false beliefs are more likely to motivate us to behave in inappropriate ways. For example, we found out that lead is poisonous and we try to make sure children’s toys no longer contain lead for that reason. People felt free to put lead in children’s toys until their beliefs were corrected.
  4. Many people want to manipulate us to believe certain things, and understanding good argumentation can help us spot the faulty arguments that are used to manipulate us. For example, charlatans want to sell us products that don’t actually work. Many medical products are sold that don’t actually do what they are said to do. People waste their money on those products when they get duped.

Update (3/8/13): I clarified how epistemology relates to good argumentation and rationality.

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