Argument

Argument

It is widely accepted that problems with writing are often closely intertwined with a lack of training in thinking critically; for that reason coverage of some basic concepts in critical thinking is included here. Of course thousands of books have been written on critical thinking and logical argument—and on the subtleties of logical argument in English. It is not possible here to do more than touch on a few key distinctions.

Deductive/Inductive

The conclusion of a deductive argument is based on its premises, and the conclusion must follow logically from the premises if the argument is sound. The classic examples of deductive arguments are syllogisms.

Example:

A successful baseball team must have good starting pitchers to succeed. This year's White Sox team does not have good starting pitching. Therefore, this year's White Sox team will not be successful.

Note that the reasoning of a deductive argument may be valid even if one of its premises is false. For example, the above syllogism makes a valid argument in terms of its reasoning, regardless of whether or not it is in fact true that to be successful a team must have good starting pitching.

Inductive arguments, on the other hand, rest on factual evidence; typically they generalize from a particular number or percentage to a general conclusion.

Example:

Since the creation of the National League, every World Series winner has had at least three outstanding starting pitchers on its roster. It seems reasonable to conclude from this that a team with fewer than three outstanding starting pitchers has an extremely slight chance of winning the World Series.

Notice that inductive arguments are based on numbers, percentages, and estimates of probabilities.

In practice, arguments very frequently combine inductive and deductive elements.

Example:

Almost no one ever dies from this sort of operation. If Frank dies during the operation, then it must be as a result of malpractice on the part of the surgeons. We should sue!

The initial claim here involves an inductive claim. It can only be settled by reference to the facts:

What percentage of people have in fact died during this sort of operation?

The follow-up claim represents a deductive argument, and can be addressed by reasoning, without reference to the facts of the case:

If it is indeed true that others have not died during this sort of operation, then what are the possible explanations? Is it in fact true that the only possible explanation is medical malpractice?

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