Induction Deduction

As a guideline, we can say that inductive logic starts from observation of particulars and makes general conclusions, whereas deductive thinking begins from general statements and makes conclusions about particulars.

What is a logical statement?
A logical Statement needs two or more premisses in order to make a conclusion. If you only have one premiss, then you are giving me a definition. THe premisses that form an individual argument are co-premisses. This means that the logical argument will not be complete with only one of the premisses. When both premissess support each other, they are known as co-premisses because they are both necessary for the syllogism to be logically valid.

Deductive statements
Deductive logic arrives at necessary conclusions— Assuming that our premisses are true, the conclusion then mustbe true as well. This is because we go down levels of abstraction. If the premisses are true, the conclusions are necessarily true because the conceptual content of the conclusion is included in the premisses. In other words, deduction doesn't give you new information, and all the terms in your conclusion need to appear in the premiss.

Keep in mind that deductive logic is not concerned with the truth of the statement. It's only about the relationships of the terms. Therefore we don't speak about the truth of a logical statement, but only say that it is valid or invalid. The example below is a statement that is valid, but definitely not true.


Inductive logic
Inductive logic is based on experience. Instead of valid/invalid, the conclusions of inductive logic are said to be strong/weak/worthless. Inductive arguments begin from particulars and move to general statements - we go up levels of abstraction.

If something is very probable based on our experience, then our conclusion are said to be strong.

If something seems higly improbable based on experience, then our conclusions are said to be weak

If the conclusion has no link to the premisses, even though we still move inductively from particular to general, it isInductively worthless

When using inductive logic, the truth of the premisses matters tremendously. Induction requires a correspondence between the premisses and reality to make strong claims.

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License