Substitution (logic)

Imagine you have a secret code that you use to talk to your friends. This code allows you to replace some words with other words, so only you and your friends can understand what you're saying. This is what substitution means in logic too!

In logic, we use letters and symbols to represent different things. For example, we might use the letter "A" to represent the statement "It is raining" and the symbol "¬" to represent "not". So, "¬A" would mean "It is not raining".

When we do substitution, we take a letter or symbol and replace it with another letter or symbol that means the same thing. For example, we could replace "A" with "B" and "¬" with "~". So, instead of "¬A", we would have "~B", which still means "It is not raining".

Substitution allows us to simplify and clarify our logical expressions. Just like your secret code helps you communicate with your friends, substitution helps us communicate with other people who use logic.