Principles of Logic and other concepts

There are some laws and principles of thought that are associated with good reasoning. Following these laws and principles lead to good reasoning.

Of the laws of thought, three serve as foundation for all other laws. This implies that any pattern of thought, or any acceptable rule of inference must never violate these basic laws of thought.

The three main principles of logic are :

a. Law of identity

b. Law of excluded middle

c. Law of contradiction

A. Law of identity. 

This law assert that if any statement or proposition is true then it is true. Each thing is identical to itself.

For example, A is A. That is, a thing is said to be what is.

Another example is "an apple is an apple".

This law is fundamental to human reasoning. It is the basis for the definition of terms, persons or objects.

B. Law of excluded middle.

This law assert that a statement must be either true or false. This means that anything must be either A or not A and there is no middle position between A and not A. 

In other words, a proposition or its negation must be true. For example, no sitting on the fence is allowed, one must take a stand. Another example is if "it is raining" is not true then "it is not raining" will be true. 

This principle requires one to be categorical when making assertions. 

C. Law of contradiction. 

This assert that no statements can both be true and false i.e a proposition cannot both be true and false in the same context, at the same time and in the same place. 

This means that the statements that contradict themselves are not acceptable.   Nothing can be A and not A at the same time. It is either an Apple or it is not. It cannot be an Apple and not an Apple. 

For example, "Fred is a boy" and "Fred is not a boy" cannot both be true in the same context, time and place. 

Other concepts 

1. Principles of bivalence

Each statement is either necessarily true or necessarily false. 

2. Tautology 

A tautology is a proposition that is true in all possible cases. 

3. Law of commutativeness

This law applies to conjunctions and disjuctions. It states that the arrangement of the positions of the components of a conjunction/disjunction does not alter the truth value of the proposition. 

4. Law of associativeness

This law is also associated with conjunction and disjunction. It asserts that the arrangement of order of parentheses (brackets) of a conjunction/disjunction does not alter the truth value of the proposition.