أنه علم بقوانين تعصم مراعاتها الذهن عن الخطأ في الفكر
It is knowledge of rules whose observance protects the mind from error in thinking.
Its key expressions are:
Rules: standards for examining thought.
Their observance: not merely knowing the rules but applying them correctly.
Error in thought: faulty conception or inference that prevents proper understanding or conclusion.
The definition therefore means protection through the correct observance of rules, not a magical absence of error.