This commensurability between the formal syllogism and...

This commensurability between the formal syllogism and analogy is defended by al-Farabl when he uses what he calls "inference by transfer" or, as he notes of the mutakallimiln, "inference from evidence to the absent", or, as Kant would have it, from the phenomenal to the noumenal realms. The act of transference requires that the syllogism have a middle term, what analogy calls similarity.

AI-Farabi further contends that, "if we are determined to have the 'transfer' be correct it is necessary that the 'matter' which is similar in the two compared objects be investigated. He presents a case depicting the (evident) createdness of animals or plants with the (absent) notion of createdness in the sky and the stars, and sets out to establish not only a middle term that denotes similarity, but one which also speaks of relevance.

If both similarity and relevance obtain, then analogical inference takes on the form and strength of a first order syllogism, and a causal connection is established. However, problems still arise when similarity might appear to obtain, but, in fact, does not. When this happens, analogical reasoning contains at least one faulty premise that has not been detected by those forwarding an analogical argument.

AI-Farabi refers to this distinction as the method of "raising" whereby conclusions are raised but do not obtain upon further logical investigation. However, leaving room for a legitimate analogy, al-Farabi then speaks of the method of "finding".

'Simply stated, al-Farabl reminds the reader that, "if one establishes a judgment by 'raising' it does not necessarily result that when one' finds' this thing (which is 'raised') one will 'find" the judgment (to be true); rather it is the converse of this that is necessitated, namely if one 'finds' the judgment, one 'finds' (also) the thing (in question)". In this sense, al-Farabi anticipates harsh criticisms against the analogy that he does not necessarily accept.

Inductive and analogical arguments were converted into syllogisms making the cause or similarity in analogy the middle term in the syllogism", which compounded the difficulty of defining and determining the exact limits of qiyas. The force of the inferences made in an analogy is identical to those of a first figure syllogism because the similarity (' illa) is the subject term in the major premise and the predicate term in the minor.

If the 'illa is absent when the judgment is absent...and present when the judgment is present...