Laws of logic

About 2,500 years ago a man named Aristotle discovered the rules of logic. This is Aristotlewww.biography.com... and the definition of logic is:
Logic-"The art and science of correct thinking."
So this smart man named Aristotle discovered logic and its composed of three laws.

1.The law of identity:
This law states that a thing is itself. A glass is a glass, a fish is a fish, a bird is a bird. To sum it up. A is A. If it exists it exists as something, as an identity.
aynrandlexicon.com...
"Whatever you choose to consider, be it an object, an attribute or an action, the law of identity remains the same. A leaf cannot be a stone at the same time, it cannot be all red and all green at the same time, it cannot freeze and burn at the same time. A is A. Or, if you wish it stated in simpler language: You cannot have your cake and eat it, too."


Second law-The law of Non Contradiction:
A contradiction cannot exist. A glass cannot be a glass and not a glass at the same time and in the same respect. You can't be 60 years old and 20 years old at the same time, you can't be reading this and not reading this at the same time, you...get the point. aynrandlexicon.com...
The third and last law is-The law of excluded middle. This can be stated as "it's either A or not A. It's either a glass or it isn't, it's either a fish or it isn't. Yes or no. It will either rain tomorrow, or it will not. There is no middle ground. web.stanford.edu...

To sum it up.
Law of identity-A is A
Law of Non Contradiction- A cannot be A and not A at the same time.
Law of excluded middle-It's either A or not A.
Hope you find this helpful!

a reply to: Aristotelian1
Most of ATS could use a lesson in logic.

a reply to: Aristotelian1

Meh

Aristotelian logic has it's place in things like computer programming, i.e. "If this, then that". But it doesn't apply to philosophy, psychology, chemistry or quantum states.

a reply to: Aristotelian1

That black and white form of observation is unimaginative. Gray always exists. A glass has more than one possible use. Opposites have a neutral state. Contradictions do exist and when they are difficult are paradoxes.