Testing for Validity

Using your logical brain.

Information is often presented in the form of arguments.

Premises (that may or may not be true) are supplied, and conclusions are drawn based on those premises.

As the person on the receiving end, it is your job to determine not only the accuracy of the information presented, but also whether or not the conclusion logically follows from the premises.


Test Yourself!

Here is an example of a set of premises, followed by a list of possible conclusions. Determine which single conclusion should be matched with the premises to form a valid argument:

Premises given:

  • Some Sparrow College lacrosse players are physical education majors.
  • All Sparrow College physical education majors coach sports part-time.
  • Some Sparrow College physical education majors play on professional sports teams.

Which one of the following conclusions necessarily follows from the 3 given premises above?

  1. Some Sparrow College lacrosse players play on professional sports teams.
  2. All part-time coaches at Sparrow College are physical education majors.
  3. Anyone from Sparrow College who plays on a professional sports team also coaches part-time.
  4. Some individuals from Sparrow College who play on professional sports teams also coach part-time.
  5. Not all Sparrow College lacrosse players coach sports part-time.

The correct answer is 4.

Why?

It logically follows from the second two given premises. Since all Sparrow College physical education majors coach part-time and some in that group of physical education majors play on professional sports teams, it follows that some who play on professional sports teams also coach part-time. The premises do not supply enough information to draw conclusions 1-3 or 5.

«  Determining Accuracy  |  Unveiling the Source  »

In This Tutorial: