The Blog

An argument can be logically sound but still be false. If so, how else can truth be known?

Here is an argument:

1. All men are four-legged reptiles;
2. Zachary is man;
3. Therefore, Zachary is a four-legged reptile.

Logically, this argument makes sense, but we all know it is not true.

The argument is valid because the conclusion follows from the premises. But the conclusion is false because the first premise is false.

In other words, an argument can be logically sound but still be false because the premises do not correspond with reality.

We need some more information to discover truth.

We get that information from observing the world around us and drawing general conclusions from those observations.

When you observe something over and over again, you may conclude that a general principle is true.

For example, when you repeatedly drop an object off a table, you naturally observe that the object always falls to the ground- gravity. This method of drawing general conclusions from specific observations is called induction.

In order to be clear, we need to distinguish from induction and deduction.

• The process of lining up premises in an argument and arriving at a valid conclusion is called deduction.
• But the process of discovering whether the premises is true is called induction.

Much of what you know, you know by induction. Most conclusions based on induction cannot be considered absolutely certain but only highly probable.

For example, are you absolutely sure, 100 percent certain that gravity makes all objects drop?

No, because you have not observed all objects being dropped.

Likewise, are you absolutely certain that all men are mortal?

No, because you have not observed all men die.

Personal Reflection:

So if inductive conclusions are not certain, can they be trusted?