New logic category

Added a new Logic category today.

Examples of logic includes:
If you don't visit someone when they're dead, why visit them when they're alive?
Conversely, if you don't visit someone when they're alive, whenwhy visit them when they're dead?

If x = y, then y = x, ie,

if x equals y, then it must be true that y equals x.

Other examples include:
Crying releases chemicals that relieves the body of stress. Therefore, when stressful, crying is logical, -> if stressful, then cry. ;o)