66. Proof of Fact and Causal Demonstration. -- Corresponding to the fundamental distinction between the syllogism with a certain conclusion and the strictly scientific demonstration is the Aristotelean division of the proof of fact and the causal demonstration.

The demonstration hoti, demonstratio quia, or quod (quia meaning not because, but that), is the proof that something is. According to Cajetan, this proof bears both on the copulative to be and upon the existence, especially on the latter.^{1}

The causal demonstration dioti, demonstratio propter quid, brings into evidence the immediate cause of the thing demonstrated, the proper reason, arche oikeua, for which it is. This is why it is strictly scientific.

A demonstration which gives an extrinsic or a general reason for the connection of the predicate with the subject is not a demonstration dioti. but is ranked among proofs of fact.

{1} Posterior Anal., II, L