In argumentation, statements are provided to prove something that is actually true. However, sometimes the arguments might be provided to prove a conclusion that might be false. For understanding whether premises provide the necessary support for the conclusion. For this, there is a need to learn how to distinguish between the two forms of arguments. This distinction can be expressed in the form of deductive and non-deductive arguments.
What are Deductive and Non-Deductive Arguments?
A deductive argument is an argument that has an absolute conclusion. This argument has both a true conclusion as well as a true premise. When the premises of an argument support the conclusion deductively, we say that the conclusion follows deductively from the premises. Deductive support is the strongest kind of support that premises can give to a conclusion. When the arguments support a conclusion to some significant degree but do not follow a deductive pattern then these arguments are known as non-deductive arguments.
Deductive arguments provide strong conclusive support for their conclusions, while non-deductive arguments provide strong, probable, but inconclusive support for their conclusions.
Deductive Arguments
A deductive argument is presenting statements that are known to be true and provide strong support for the conclusion. Deductive reasoning relies on what is assumed to be known to infer truths about similarly related conclusions. It can be said that in deductive arguments the conclusion will be true if the premises are true. The kind of support intended in deductive arguments is infallible and forms the basis of a sound argument.
Here are some of the phrases that are used to indicate deductive arguments.
| Deductive argument indicators |
|---|
| it necessarily follows that … |
| it logically follows that … |
| it absolutely, necessarily, or certainly follows that … |
Following are some of the examples of deductive arguments:
- It is raining heavily outside. If it is heavily raining, then Jimmy will be carrying an umbrella. This necessarily follows that Jimmy will be carrying an umbrella.
- Students are happier reading fictional books. The town library has a wide range of fictional books. Therefore, students are happier reading at the town library.
- Most dogs have brown eyes, Dash is my dog. So it follows that Dash has brown eyes.
Non-Deductive Arguments
Non-deductive arguments are based on the forms of experiences you have had, it involves forming generalisations and in a strong non-deductive argument if the premises are all true, it is rightfully expected that the conclusion will also be true, however, there is a possibility that the conclusion might be false. The support provided for the conclusion is a matter of degree. The premises of a strong non-deductive argument make it probable that the conclusion is true.
Similar to deductive arguments, there are indicators of non-deductive arguments
