Logic is the science of reasoning.
It helps you decide whether something (known as argument) is true or false.
A valid argument is one where there is a specific relation of logical support between the assumptions of the argument and its conclusion.
The concepts of logic was formally built by Greek philosophers and mathematicians. It later became the corner stone of science & industrial revolution in Europe.
Critical thinking is reasonable, reflective & logical thinking focused on deciding what to believe or do.
Logic is closely related to mathematics. However, logic has broader usages into linguistics, law and philosophy.
Critical thinking - Logical reasoning as oppose to blind faith or influence
Root cause analysis
Overall understanding of the systems & phenomena