Right now there is some discussion of having a higher profile dialogue between Catholic scholars. That will likely be very interesting to get into this.
I’ve had some extended exchanges with Kemp. You will notice that his objections are theological, not philosophical. That is important. He agrees that the GAE is logically possible, but the questions it raises are theological. I’m not as informed about how this work as I am sure you are, but there is a particular logic and process to thinking through theological questions in Catholicism, and philosophers (such as you and Kemp) cannot do it alone.
Another way to put it is this.
Can there be rational minds outside the garden? There certainly is not a logical contradiction. The real question is if it conflicts with Catholic doctrine. I observe that it does not directly contradict with Humani Generis, and in fact is an open question in Catholic theology.
Can those rational minds outside the garden be, apparently, sinners? I note that Kemp and you are using a surprisingly flattened definition of “sin,” and you need this flattened definition for your objection to stand. In theology and Scripture, sin is a concept has far more theological depth and complexity (see for example Romans 5:10-14, which literally says that sin was in the world before Adam).
In the same way that you and Kemp resolve the polygenesis vs. monogenesis conflict with a distinction, the same approach is possible here. Perhaps a particular type of sin arose with Adam (which we might call Adam’s sin). Perhaps other types of sin or wrongdoing (as I prefer to call it) were outside the Garden, but were not as severe or consequential not Adam’s sin.
You must grant that this is logically possible, so strictly philosophical objections are going to fail. The real question: does this contradict Catholic theology as it is? Can Catholic theology change to accomodate this? These are not philosopher’s questions, but theologians questions. That is important, becuase it clarifeis what the real barriers are. The problem is not the illogic of rational souls outside the garden who are not perfect, but the theological questions that arise.
I believe those theological problems are easily resolved. It is not that I am doing anything unique or surprising here, but appealing to traditional theology. Scripture is not about rational souls on other planets. Historically, it has been understood to be about Adam and Eve and their descendents. That means it does not speak of people before Adam and Eve, but it also does not speak of them, their nature, or their theologicla status.
The Catholic Encyclopedia (1911), 12: 370–371:
The question whether we can admit the existence of Preadamites in the strict sense of the
word, i.e. the existence of a human race (or human races) extinct before the time of Adam or
> before the Divine action described in Genesis 1:2 sqq., is as little connected with the truth of
> our revealed dogmas as the question whether one or more of the stars are inhabited by
> rational beings resembling man. Palmieri (“De Creatione”, Prato, 1910, p. 281, thes. xxx) does
not place any theological censure on the opinion maintaining the past existence of such
Preadamites, and Fabre d’Envieu (“Les Origines de la terre et de l’homme”, Paris, 1873, lib.
XI, prop. 1 [Correction: this should be Bk 2, Prop 50—KWK]) defends the theory as probable
That is a key point. The GAE reduces the problem to be no more challenging than finding out there are rational souls on other planets. Certainly that would raise theological questions, but it does not actually contradict the story of Scripture. So how do Catholic theologians respond?
That seems to be the crux of the question to explore here. I’ve only informally laid it out, but at this point it seems clear that this is right at the boundary of Catholic theology. Scholars should be cautious, as is Kemp, which is why it makes sense to reject it right now. But the reality is that this is an open question, and an exciting one at that. I don’t see that Catholic theology has engaged this question with an eye to exploring what is possible, and perhaps as theologians enter the conversation we might clarify that this is a permissible view.
So I hope that explains more where this is going @AntoineSuarez. If you have ideas on how to have that conversation, and the right venue for an exchange, let me now. I’m looking forward to the conversation.