Pashuteh, He merely referenced the REMA’s statement, not his own pshat or point.
Medrash Tehillim (19) quotes Shmuel as sayign he is an expert in the streets of Nehardea as much as he is an expert in the ‘streets’ of the heavens. the Medrash asks how Shmule knew all of that, and it answers he knew it all through the Torah. It then quotes a R, Hoshea as saying there is “space” between the upper waters and the firmament, and the Medrash asks how R, Hoshea could know this unless he traveled to space. It answers, he knew it from the Torah.
The Gemora in Bechoros 8a derives from a posuk in Bereishis the fact that gestation period of a snake is longer than the rest of the animal kingdom. This is cited by the Ramban (Toras Hashem Temima p.159 in Chavel edition) as but one example of how Chazal knew facts of science from the pesukim in the Torah that describe Brias HaOlam. He cites more. He says “the sages of Yisroel have knowledge through these pesukim of all of creation.”
Rabbeinu Bachyai writes in the Introduction to Chumash that all wisdom and science in existence is contained in Torah.
The Chosid Yaavatz (Ohr Hachaim) says that chazal knew science form a Mesroah that goes back all the way to the Neviim, who knew it from Hashem, without any effort at all.
Particularly interesting is a statement on this topic in the Aruch Hashulchan (EH 13). Quote:
“I will tell you a great principle: Chazal, besides their holiness and wisdom in the Torah, were also greater scholars in the natural sciences those savants(“mischakmim”) who would argue against their pure words. And someone who disagrees with them testifies about himself that he does not believe in Torah she bal peh, even though he would be embarrassed to admit it outright.”
Chasam Sofer (Beshalach) writes that this is the meaning of the posuk “Ki hi chachmascha ubinascha l’einei ha’amim” – Chazal were great experts in the secular sciences and disciplines. In fact, you need to know much secular knowledge in mmany areas in order to properly understand the Torah – and he gives several simple examples. However, since we are supposed to be busy learning Torah – not secular science – all day and night, and Hashem has no “nachas ruach” from us learning secular studies at all, how would Chazal have known all the secualr wisdom that they clearly knew, as we see they did from all of Shas?
Answer: They knoew it from the Torah, since the entire body of secular wisdom is included in the Torah, for the Torah is the bluepeint of the world. And so, when the Goyim see that we do not study the secular science books at all – and we even disagree with them! – yet we derive all the secular knowledge, in the most precisely accurate form – from only the Sefer Torah, they will exclaim, “Am chacham v’navon hagoy hagadol hazeh!” (A similar explanation is given by the Raavad-ibn Daud. He says that the posuk refers to the philosophical truths that it took the nations centuries to develop, we knew all the time via tradition from Har Sinai.)
Not only do we see that Chazal learned their science from the Torah, but Rav Breil, the Rebbi of the Pachad Yiztchok teaches us that we do not even entertain the possibility of a scientific statement in Chazal not coming from the Torah .This we see from Rav Briel’s answer to the Pachad Yiztchok’s question regarding the killing of lice on SHabbos. The Gemora permits it, based on a scientific fact. The Pachad Yiztchok asked his Rebbi that due to the possibility that this scientific fact is incorrect, perhaps we should be machmir and not kill lice on shabbos, just in case.
Once we establish that the scientific knowledge that is incorporated into Torah Shebal Peh is derived form the Torah, it has the same status as all of Chazal’s interpretaitons of the Torah — they are binding:
The Gemora in Sanhedrin (100a) tells that R. Yochanan derived from a posuk that when Moshiach comes, the gates of Jerusalem will be made of jewels 30 amos long and 30 amos high. Some student said that such big jewels do not exist – “we do nto even find jewels as big as doves eggs,” he said. Then, one day the student saw angels (!) cutting such big stones, and he asked them what they are for. The angels answered: “They are for the gates of Jerusalem”. When next he saw R. Yochana, he praised his qualifications for expounding the Torah, based on his “scientific observation” that confirmed the Rebbi’s interpretation.
R. Yochanan responded, “Bum! You only believe because of what you see? You dishonor the words of the sages!”, and the student died.
The Ran (Drashos #13) points out that the statemnt of R. Yochana had no halachic relevence at all – it was merely an Agadic interpretation, and the disagreement was regarding a scientific fact, yet the student was punished for not believing in its truth. Therefore, he concludes:
“Just as we are commanded to follow their opinions regarding laws of the Torah, so too are we commanded to follow all of what they say from tradtiion in Hashkafa (“Deos”), and medrash on Pesukim. And someone who veers from their words, even in somethgin that has no relevence to any Mitzvah, is an Apikores and has no share in the next world.
The Radvaz (4:232) writes that “Aggadah is part of the Torah shebal peh and is rooted in what Moshe receieved on Har Sinai directly from Hashem, just like the rest of Torah shebal peh”.
Similarly from the Alshich: “Nobody has a right in our generation to disagree based on his own opinion, if he did not find such an opinion from his predecessors (Rebbeim). We are commanded “lo sosur”, which includes also Agadita.” (Shmuel II 21:1)
The Sifri (48) explains the posuk in Devarim 11:22, “And you really follow all this Mitzvah”, that “this means to learn Midrash, Halachah, and Agada.”
Rav Yiztchok Izak Chaver in Magen Vtzenah (p,49) – there are people who reject Chazal’s statemetns because the secular scientists disagree (he gives examples, such as the sun rising above the firmament at night etc), and they laugh saying that we know its not true. they are fools. The {b]GAR, who even the scientists admit that he knew science much better than them, accepted all words of Chazal as fact, and that the philosophers and scientists (chachmei hatechunah) are all wrong, and he believed in the truth of the simple straightforward understanding of the words of Chazal. The GRA said that the scientists didnt come to the ankles of our sages in any secular discipline or science.
Chida (Shem Hagedolim: “Seforim”:5:82) – There are a minority of Gedolim among us who disagreewith Chazal because of their scientific knowledge, but they do not understand that Chazal had Eliyhau Hanavi informing them, and they had Ruach HaKodesh to inform them.
Chasam Sofer — Please see the Chasam Sofer in Beshalach I quoted above. He says the same thing in Drashos Chasam Sofer Vol. 1 p.100b. Our phophets and sages know all the sciences much better than the scientists even though all they learn is Torah. This is because the One Who created nature informs our sages of the corretc facts. This is what amazesthe Nations, as it says, Am navon v’chacham hagoy hagodol hazeh!
An identical interpretation to that of the Chasam Sofer’s explanation Am navon v’chacham(I quoted one earlier in the name of ibn Daud regaridng philosophical knowledge) is found in the Ramak (Sefer HapPardes 13:6) regarding astronomy.
From the Maharal (Ber Hagolah 6):
The Maharal is explaining why Chazal sometimes seem to contradict what science says:
[Chazal] [physical] descriptions, but rather the words of our sages refer to the essence, and have no relation to the outer, material matter.