What Is a Logical Argument?

Logical arguments follow a particular course of reasoning with the goal of determining if something is true or false, sound or valid. Some logical argument styles use inductive reasoning and some use deductive reasoning. Types of inductive reasoning in logical argument includes generalization, false analogy, casual inference, and prediction. Deductive reasoning bases it's soundness or validity on the accuracy of the initial premise. All logical arguments have a premise and a conclusion and derive their conclusions from the veracity of the premise or amount of amount of accurate information contained in the premise.

Every logical argument may be classified as using either inductive reasoning or deductive reasoning. Inductive reasoning typically moves from specific to general using individual events, incidents or generalizations to support an argument and arrive at a conclusion. An example of inductive logic is making an observation that all spiders that have been observed by a person are aggressive, therefore, all spiders are aggressive. This type of logic has been criticized for its apparent weaknesses in that it draws conclusions based on the limited experience of the observer or the amount of truth contained in the premise. In a mathematical logical argument, stronger induction is used to demonstrate that gravity has an expected effect on moving objects based on simple observation. These observable, provable conclusions regarding gravity, although seemingly absolute, are not accurate when those same moving objects approach the speed of light.

Inductive reasoning used in logical argument states that a man may notice through observation that when he throws a stone up into the air, it falls back to the ground. If he throws another stone that will likely fall back to the ground, too. Deductive reasoning used in logical argument is based upon the premise of a known, proven fact or law of gravity that when a stone goes up, it will come down every time. The difference is in the way each type of argument is expressed. Inductive reasoning is supported by the man's observation of events around him. Deductive reasoning is supported by a stated fact or law of physics.

Both inductive and deductive require different kinds of support. In the previous example, the first man's inductive reasoning is supported by what he sees and may be supported further by what he sees each time he throws a stone, even if he never realizes Newton's law of gravity. The man using deductive reasoning to support his logical argument relies on the known, provable law of gravity, and his conclusion is supported by the laws of physics, even if he never throws a stone. While inductive reasoning relies on inference and generalization based on what is observed, deductive reasoning bases the conclusion on the veracity of the initial premise. A logical argument that uses deductive reasoning is never true or false. Rather, it is valid or invalid.

Inductive reasoning typically reaches a conclusion based on experience or observation while deductive reasoning reaches a conclusion based on rules, laws or other established facts or principles. Deductive reasoning begins with the general and moves toward a specific conclusion. An argument that uses deductive reasoning is never true or false, rather it is valid or invalid.