Thursday, December 29, 2005

The truth status of doctrines

It is important to consider the two types of argument identified in logic when we think about doctrine: 1) deductive 2) inductive. All arguments have a conclusion supported by one or more premises intended to support the conclusion (otherwise it wouldn't be an argument -- it would be some other sort of communication). In a deductive argument, the premises are considered to provide conclusive support for a conclusion. In other words, if the premises are true then the conclusion, by necessity, follows. If the premises are, in fact, true, then we can be confident that the conclusion is true. In an inductive argument, the premises, although true, do not lead to the conclusion by necessity. In other words, the conclusion is a matter of probability. Let me give a couple of simple examples: 1) This argument is deductive:
  1. All humans are intelligent.
  2. Steve is a human.
  3. Therefore, Steve is intelligent.

If we assume that the two premises are true (some might dispute #1 or, in my case, #2) then the conclusion must follow from the premises. In other words, if the premises are true then it is impossible for the conclusion to be false.

2) This argument is inductive:

  1. Most humans are intelligent.
  2. Steve is a human.
  3. Therefore, Steve is intelligent.

Even if we assume that the premises are true, the conclusion that Steve is intelligent does not necessarily follow. The first premise leaves open the possibility that some humans are not intelligent. The fact that most humans are intelligent means that it is highly probable that Steve is intelligent, but it doesn't necessarily follow that he is. He could be in the minority of humans who are unintelligent. More correctly stated, the argument should be:

  1. Most humans are intelligent.
  2. Steve is a human.
  3. Therefore, Steve is probably intelligent.

In inductive arguments, there is always a degree of uncertainty regarding the conclusion.

Now, here is the question to consider. A doctrine is a statement of a conclusion. For example, the doctrinal statement that 'Jesus Christ is fully human and fully divine' is a conclusion based on a whole range of evidence and reasoning. In other words, this doctrinal statement has been arrived at as the result of argument. But what type of argument is it? Deductive or inductive?

If the statement that "Jesus Christ is fully human and fully divine" is the result of a valid deductive argument then we can evaluate the conclusion as being absolutely certain. If, however, the statement is the result of an inductive argument, then we can only evaluate the conclusion in terms of how probable it is true. Most doctrinal statements are the result of inductive arguments and, therefore, can only be held to be true in a probabilistic sense. This is why there are so many variations in belief and why it is so difficult to persuade others of what we, ourselves, may believe to be true.

The issue of induction also requires intellectual humility on our part when we make doctrinal claims. If most doctrinal statements are the result of inductive arguments, then it is always possible that we may have it wrong. We always need to be open to the possibility that new evidence might come along that will require a modification in our conclusions (doctrines).

Intellectual humility is one of the key traits of a critical thinker. Paul & Elder (2002) define intellectual humility

as having a consciousness of the limits of one's knowledge, including a sensitivity to circumstances in which one's native egocentrism is likely to function self-deceptively. This entails being aware of one's biases, one's prejudices, the limitation of one's viewpoint, and the extent of one's ignorance. Intellectual humility depends on recognizing that one should not claim more than one actually knows. It does not imply spinelessness or submissiveness. It implies the lack of intellectual pretentiousness, boastfulness, or conceit, combined with insight into the logical foundations, or lack of such foundations, of one's beliefs.' (p. 22)

Each of the biasing factors identified in the above definition leads to the probability that most of our thinking is inductive. It is very rare to find a deductive argument for the most significant issues we consider. Knowing the difference between a deductive argument and an inductive argument keeps us humble about what we know and keeps us inquiring to further refine what we believe.


Paul, R & Elder, L (2002), Critical Thinking: Tools for Taking Charge of Your Professional and Personal Life, Financial Times/Prentice Hall, Upper Saddle River, NJ.

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