Vaughn - Concise Guide to Critical Thinking - Chapter 08 Summary

CHAPTER 8 SUMMARY

Explanations and Inference

  • Even though an explanation is not an argument, an explanation can be part of an argument. It can be the heart of the kind of inductive argument known as inference to the best explanation.
  • In inference to the best explanation, we reason from premises about a state of affairs to an explanation for that state of affairs. The premises are statements about observations or other evidence to be explained. The explanation is a claim about why the state of affairs is the way it is. The key question that this type of inference tries to answer is, What is the best explanation for the existence or nature of this state of affairs? The best explanation is the one most likely to be true, even though there is no guarantee of its truth as there is in deductive inference.

Theories and Consistency

  • In inference to the best explanation, there are special criteria we can use to determine the best theory. Before we apply these criteria, though, we have to make sure that the theory in question meets the minimum requirement of consistency. A theory that does not meet this minimum requirement is worthless, so there is no need to use the special criteria to evaluate the theory. A theory that meets the requirement is eligible for further consideration. Here we are concerned with both internal and external consistency.

Theories and Criteria

  • The criteria of adequacy are reasonable criteria and reliable procedures for judging the merits of eligible theories and for arriving at a defensible judgment of which theory is best. The criteria are the essential tools of science and have been used by scientists throughout history to uncover the best explanations for all sorts of events and states of affairs. Science, though, doesn’t own these criteria. They are as useful—and as used—among nonscientists as they are among men and women of science.
  • A theory judged by these criteria to be the best explanation for certain facts is worthy of our belief, and we may legitimately claim to know that such a theory is true. But the theory is not then necessarily or certainly true in the way that a sound deductive argument’s conclusion is necessarily or certainly true. Inference to the best explanation, like other forms of induction, cannot guarantee the truth of the best explanation.
  • The criteria of adequacy are testability (whether there is some way to determine if a theory is true), fruitfulness (the number of novel predictions made), scope (the amount of diverse phenomena explained), simplicity (the number of assumptions made), and conservatism (how well a theory fits with existing knowledge).

Telling Good Theories from Bad

  • Judging the worth of a theory is a four-step process called the TEST formula: (1) Stating the theory and checking for consistency, (2) assessing the evidence for the theory, (3) scrutinizing alternative theories, and (4) testing the theories with the criteria of adequacy.
  • By applying the criteria to all the competing theories, we can often accomplish several important feats. We may be able to eliminate some theories immediately, assign more weight to some than others, and distinguish between theories that at first glance seem equally strong.

 

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