Logical Argument

There are a number of elements that add up to an adequate argument. To make it more convincing and logically acceptable, we should look into several aspects.
  • 1. Define logic of argument
  • 2. Understand formal logic
  • 3. Construct a logical argument

A logical argument consists of factual or true conditions and an undeniable conclusion. Simply put, an opinion is not supposed to stand alone but supported with firm evidence.

The definition entails from the theory about the logic of an argument, which is about the connection between the thesis and the set of reasons and considerations. [1] The reasons and considerations must be connected to the thesis such that if the reasons and considerations are accurate and persuasive, then we are driven forcefully to accept the thesis. The reasons and considerations are logically connected to the thesis, that is, they suggest strongly that if they are reliable, then the thesis must follow. [2]

Formal logic

A logically effective argument follows some basic principles of Formal Logic and some of the technical terms used about in the latter definition will be elaborated in this part.

The essence of logics lies in the study of arguments and by argument in Formal Logic, it specifically refers to a group of sentences composed with one or more premises and a conclusion. Premise here is the set of reasons and considerations in the language of Formal Logic.[3]

When the conclusion of an argument is guaranteed by the truth of the premises then it is a valid argument, namely a logical argument.[4] That is to say, under the condition where all the premises are true there is no way that the conclusion is false. In that case, it is a logical argument.

We can make the theory less abstract with a simple example:

Premise 1: All unmarried men are bachelors.
Premise 2: John is an unmarried man.
Conclusion: Therefore, John is a bachelor.

In this example it is impossible for John not to be a bachelor under the conditions that all unmarried men are bachelors and that John is unmarried. Hence, this is a valid argument which we are looking for.

Construction of a logical argument
A logical argument we are aiming to accomplish, of course, is not as simple and straight forward as the set of sentences in the illustration. However, it is useful and helpful to grab the essence and to internalize it in our argument writing.

First and foremost, explicitly state the premises. Making sure the premises as supporting evidence is relevant and necessarily connected with the claim of the argument. For instance, it can be pure reasoning and also supporting facts and examples. Moving on to the second step, apply proper inference.[5] As an argument is composed of premises and a conclusion, a necessary connection is required to lead from facts to the claim. Stating the relation between the two is the process of inference which is always introduced by phrases like “therefore” and “it implies that”. Finally, we come to the ultimate statement, the conclusion of the whole passage. In a logical argument, the conclusion should be direct and clear.


[1] http://www.webster.edu/~corbetre/philosophy/critical/logic.html

[3] http://plato.stanford.edu/entries/logic-classical/
[4] http://plato.stanford.edu/entries/logical-consequence/
[5] http://www.virtualschool.edu/mon/SocialConstruction/Logic.html

External Links
Stanford Encyclopedia of Philosophy, the passage on Classical Logic, which is written by authorities in the philosophical, provides a much more elaborate and complete theory of Formal Logic to help better understand the logic of an argument.

The wiki page on Argument offer detailed information to classify and construct an argument.