What is Reason Reason in its essence, means a logical thinking. But to understand reason first you have to understand logic. Everything that can be proven by observation and practice can be described as reason, an example of that is the laws of gravity or speed. Otherwise, what cannot be described using logic or theoretical thoughts , it's called emotion or faith. But to me even emotion can be seen using the reason . In short ,to most of the thinkers, reason is what you can see and prove and emotion or faith is what you can feel and can’t prove to others.