Difference Between Truth and Validity

The key difference between truth and validity is that truth is a property of premises and conclusions whereas validity is a property of arguments.

Truth and validity are two qualities of an argument which help us to determine whether we can accept the conclusion of argument or not. Truth is the quality of a statement being true or accurate. An argument is valid when its conclusion follows logically from the premises.

CONTENT

1. Overview and Key Difference
2. What is an Argument
3. What is Truth
4. What is Validity
5. Relationship Between Truth and Validity
6. Side by Side Comparison – Truth vs Validity in Tabular Form
7. Summary

What is an Argument?

In the field of philosophy and logic, an argument is a series of statements that usually help to persuade someone of something or to present reasons for accepting a fact.

Figure 1: Argument Terminology

Premises and conclusions are the main building blocks of a conclusion. A premise is a statement that provides evidence or reasons to form a conclusion; an argument can have more than one premise. A conclusion in an argument is the main point the arguer is trying to prove. Thus, an argument has only one conclusion and one or more premises.

What is Truth?

Truth is a property of premises and conclusions. A premise in an argument can be either true or false. The conclusion derived from these premises also becomes true or false accordingly. Moreover, it is possible to determine the truth of an argument by several factors. Common sense, personal experience, investigation, and experiment are some of these factors. Let’s look at some examples:

All German Shepherds are dogs. – true premise
All cats are yellow. – false premise

What is Validity?

We always use the terms validity and valid to describe an argument. We consider an argument as valid when its conclusion follows logically from the premises. In other words, it is impossible for the premises of an argument to be true while the conclusion is false. Moreover, the conclusion is always a logical consequence of its premises. Let’s look at an example to understand this concept better.

All men are mortal. – true premise
Socrates is a man. – true premise
Therefore, Socrates is mortal. – true conclusion

Figure 02: A Valid Argument

However, true premises and a true conclusion doesn’t necessarily make a valid argument. It is the logical necessity of the conclusion according to the premises that makes a valid argument. For instance, the following argument has false premises and a false conclusion, but it is a still valid argument since it follows the same logical form as the above example.

All cups are red. – false premise
Socrates is red. – false premise
Therefore, Socrates is red. – false conclusion

Furthermore, an argument that is not valid is called an invalid argument. An argument can be invalid even though it has true premises and a true conclusion. This happens when the conclusion does not follow deductive reasoning.

All men are immortal. – false premise
Socrates is a man. – true premise
Therefore, Socrates is mortal. – true conclusion

Although we can consider the above conclusion as true, this is not a valid argument as the conclusion contradicts the deductive logic of the premises.

What is the Relationship Between Truth and Validity?

True premises and a true conclusion doesn’t necessarily make a valid argument; false premises and a false conclusion also can result in a valid argument.
True premises and a valid argument results in a true conclusion.

What is the Difference Between Truth and Validity?

The key difference between truth and validity is that truth is a property of premises and conclusions whereas validity is a property of arguments. Furthermore, a significant difference between truth and validity is that the truth of a premise or a conclusion is determined by various factors such as common sense, personal experience, investigation, etc. whereas, an argument is valid when the conclusion follows logically from the premises.

Below infographic summarizes the difference between truth and validity.

Summary – Truth vs Validity

Truth and validity are two qualities of an argument that help us to determine whether we can accept the conclusion of argument or not. The key difference between truth and validity is that truth is a property of premises and conclusions whereas validity is a property of arguments.

Reference:

1. “Introduction to Philosophy/Logic/Truth and Validity.” Wikibooks, Wikimedia Foundation, Inc., Available here.
2. “Validity (Logic).” Wikipedia, Wikimedia Foundation, 19 Feb. 2019, Available here.

Image Courtesy:

1. “Truyện vui logic” By Nguyen Hung Vu (CC BY 2.0) via Flickr
2. “Argument terminology used in logic” By Farcaster – PowerPoint slide based on argument terminology (CC BY-SA 3.0) via Commons Wikimedia