Ben Levi: I am not a fan of Rabbi Slifkin in the slightest for numerous reasons, but he does have a leg to stand on. Rav Avraham Ben HaRambam stands firmly in his corner. It’s in Sefer HaMaspik and other places. The Chizkuni also turns things into allegories similar to what Slifkin likes to do. He has Rishonim that back him up on several things, and they are not so few.
That being said, I think he takes these Rishonim farther than they themselves were willing to go. He uses Pesachim 94b as a Ra’aya that Chazal could err in science (and his list of Rishonim that say precisely that is quite impressive) and therefore assumes that they could err in anything scientific. I think it’s a misguided approach, but I don’t think it’s Kefirah because of who he has supporting him.
The whole debate here always is on the wrong track. Anti-Slifkin camps (yourself included) always bring Mekoros that Slifkin’s Derech is untenable. But he doesn’t dispute that. He just says that he was whom to rely upon and that therefore he has to take this Derech because otherwise Yiddishkeit doesn’t make sense to him. He is not denying those against him. So you bringing in 1 or 3 or even 10 more Mekoros against him doesn’t do anything in this dispute. He has proven, in my opinion, that his opinion (or at least opinions similar to his own; as I said, he goes too far with it) is one that has support in the Gedolei HaRishonim, even if other Gedolei HaRishonim are against him.
And this is where things get woefully misrepresented. There are people who are so sure that Slifkin’s Derech is so far beyond the pale that no one legitimate ever considered it. Because of this, they dismiss, ignore, or just write out dozens of Rishonim. It is unfortunate when we are unable to admit that Shittos existed because we don’t like the implications thereof. In fact, that in and of itself is quite possibly Kefirah. See Yam Shel Shlomo Bava Kama 4:9.
And since you mentioned Rav Meiselman’s book, I just want to say that it is not worth bringing up in this debate. He didn’t quote anything new in all 900 pages. He gave his own readings of Rishonim that are Dachuk at best. He pretends that Shittos of Rishonim that agreed with Slifkin don’t exist. He forces himself to dismiss countless opinions in Rishonim (something he says we aren’t allowed to do) as being in error because he has to reinterpret Gemaras so that Chazal is never even close to wrong.
Basically, if this was a pure academic debate with no meaning to it, Rabbi Slifkin absolutely destroyed Rav Meiselman. Luckily for us, there are those out there who can read and explain Rishonim better than both of those. So the fact that Rav Meiselman’s response to Slifkin was very subpar does not change the fact that Rav Meiselman is more right overall than Slifkin.