That which one takes to provide a reason or motive for a judgment.  

Intrinsic Evidence.— 1. In a broad sense, the things themselves to which one attends (including propositions) moving one to formulate a judgment about them (disregarding whether or not the specific judgment formed is true or not). 2. In a strict sense, the things themselves to which one attends (including propositions) compelling one to make a true judgment about them. Some philosophers who do not distinguish between intrinsic evidence and extrinsic evidence would not distinguish broad and strict senses of “evidence.” Whether intrinsic evidence is meant in a broad sense or strict sense, it can be immediate or mediate. It is immediate when the judgment does not require reasoning. E.g., when one sees that it is raining or instantly judges that no part can be greater than the whole of which it is a part. It is mediate when the judgment is discursively implied by what is immediately evident,e.g., when it is concluded that nothing that changes can be eternal by its nature since time is a measure of change and what is eternal transcends time. 

Extrinsic evidence.— The testimony of witnesses about some matter.