Three Types of Argument

I. Deductive Argument: an argument where the conclusion follows validly from the premises.  (In other words, an argument where truth of the premises guarantees truth of the conclusion.)

Example:

All men are mortal
Socrates is a man
______________
Socrates is mortal

II. Inductive Argument: An argument where the premises point several cases of some pattern, and the conclusion states that this pattern will hold in general.  (An inductive argument will not be deductively valid, because even if a pattern is found many times, that doesn’t guarantee it will always be found.  Therefore, an inductive argument provides weaker, less trustworthy support for the conclusion than a deductive argument does.)

Example:

We have seen 1000 swans, and all of them have been white
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All swans are white

III. Abductive (or Hypothetico-Deductive) Argument:  An argument that (i) points out a certain fact, (ii) points out that if a certain hypothesis were true, we would get this fact, and so (iii) concludes that that hypothesis is indeed true.  (Abductive arguments seem to make an even bigger jump than inductive arguments: inductive arguments generalize, while abductive arguments say that successful predictions ‘prove’ a theory is true.  Abductive arguments are not deductively valid, because false theories can make true predictions, so true predictions do not guarantee that the theory is true.)

Example:

These coins conduct electricity (fact)
If these coins are made of gold (hypothesis), then they would conduct electricity (prediction).
_________________________________________________________________
These coins are made of gold.