BA PHILOSOPHY{HONS} NOTES – DEDUCTIVE AND INDUCTIVE LOGIC

DISTINCTION BETWEEN DEDUCTIVE AND INDUCTIVE  LOGIC

It is to be noted that both deductive and inductive logic provides methods and criteria to differentiate between correct reasoning and incorrect reasoning .

DEDUCTIVE LOGIC

Generally deductive argument moves from general proposition to a particular reasoning. With regard to the notion OF VALIDITY. If deductive argument is valid when its premises if true it provides conclusion grounds for the truth of its conclusion. Here the premises  and conclusion are so related  that it is obviously impossible for the premises to be true unless the conclusion  is bound to be true.

In a valid deductive  argument, if the premises are true then the conclusion is bond to be true.

A deductive argument is either valid or invalid. There is no scope for any kind of any third category.

The central task of a valid deductive argument is to clarify the relation between premises and conclusion.

In a deductive argument premises provide complete grounds for its conclusion here the premises are sufficient enough to entail the conclusion and here no additional premises are required to substantiate the conclusion.

An important point with regard to deductive reasoning is the element of necessity there the premises necessarily implies the conclusion or in other words the conclusion is necessarily implied by the premises. Thus there is an element of absolute necessity persist in deductive reasoning.

In deductive reasoning the conclusion is contained in the premises only. The conclusion is already present in the premise that is to say that conclusion cannot provide any new information than stated by the premises.

Deductive argument is just on the basis of the form or structure of the argument . Here logician is not concerned with the content of an argument.

INDUCTIVE LOGIC

In inductive logic we generally move from particular to general reasoning for instance.

An inductive argument is valid when its premises provides some support for the conclusion . It is based on the principle of probability . The greater the likelihood or probability that its premises confer on the conclusion, the greater the merit of an inductive argument.

In inductive reasoning the premises and conclusion do not share the relation of entailment that is premises maybe strong but  even when the conclusion may not be certain.

The premises in inductive reasoning nearly support  and do not entail the conclusion . In other words the conclusion is not necessarily entail by the premises.

Inductive argument may either be termed as sound/ unsound / good / bad / right / wrong/ appealing/ non appealing / convincing / non convincing . We do not use validity or invalidity for inductive reasoning.

In inductive reasoning the premises do not provide complete grounds for the conclusion. Hence the conclusion may contain more information reasoning both form and matter are used to be evaluate the argument.

The most important distinction which means deductive and inductive reasoning is the claim made about the relationship between premise and conclusion.