In some circles, the notion of intellectual “influence” has fallen into disrepute. Influence refers to a partial dependency of A on B, without specifying the nature of the dependency. Granted that it does tend to suggest a causal relation and that causality is a blunt instrument for describing relations between historical philosophers, it seems to me that the vagueness with which the causality is suggested is a saving grace. When I say A was influenced by B, I simply mean that the way that A was had some dependency on the way that B was.
The great late scholastic Francisco Suárez did develop an unfortunate theory of “influenza” as something literally passed from cause to effect in the process of causation, but this is certainly not what historians have in mind in speaking of “influence”.
More speculatively, the objection seems to concern any application of a modern notion of univocal causality to what we otherwise want to refer to as autonomous subjects. It is true that modern univocal causality and the autonomy of reason operate on entirely different levels, so directly applying the one to the other would be a category mistake. But I submit that that is not what is going on when we say A was influenced by B. (See also Agency.)
A bit of elementary Aristotelian semantic analysis is helpful here. The historic philosopher A is “said in many ways”. She participated in the autonomy of reason. Simultaneously, she was subject to many empirical determinations. “She” is said in a different way in each of the two previous sentences. Therefore, there is no contradiction and no category mistake in affirming both. (See also Historiography.)
Ever since the middle ages and the controversy over so-called Averroism, Western culture has been affected by a desire to affirm a hyper-strong concept of personal identity. Under this notion of identity, all references to persons always univocally refer to what in modern terms would be an autonomous subject. (Modern people have become so used to thinking in this actually very extreme way that they look at the ancient world and say silly things, like that the ancient world had no concept of persons or individuality.)
Kant’s Rousseauian sympathies led him to sometimes speak this way. But this is not a necessary consequence of Kant’s analysis. Kant’s analysis requires that there is an autonomy of reason in which we participate. It does not require that my empirical subjectivity subject to empirical determination somehow be equated with a transcendental subjectivity blessed with the autonomy of reason, or mysteriously replaced by it. That is precisely the difference between a good concept of the autonomy of reason and a bad concept of free will.
Here Kant’s alleged dualism is more helpful than his Rousseauian sympathies. We should say that it is a category mistake to simply equate transcendental and empirical subjectivity, or to substitute one for other in an argument.
Kant says the transcendental I has no content; therefore in particular, it has no content overlapping the content of my (or any) empirical self. It is a pure index of the unity of a unity of apperception.
I am therefore reluctant even to refer to “a” transcendental subject as if it were individuated, let alone claim it as mine.
The Platonic terminology of “participation” is useful in cases like this. Empirical “we” don’t quite have transcendental subjectivity, because it exceeds us, but we do “participate” in it. Only my empirical subjectivity’s limited participation in transcendental subjectivity is specifically mine. It is not even clear that my whole empirical subjectivity is included in this participation. “My” participation in transcendental subjectivity in any event does not make empirical me into a transcendental subject or give me ownership of transcendental subjectivity. Meanwhile, transcendental “I” am no mere subject. (“I am every name in history,” as Nietzsche said.) (See also What Is “I”?; Subject.)