here are some sources oft-quoted in such discussions:
Pesachim 94b
The Sages of Israel say, During the day, the sun travels below the firmament, and at night, above the firmament. And the scholars of the nations say, During the day the sun travels below the firmament, and at night below the ground. Rebbi said: Their words seem more correct than ours, for during the day the wellsprings are cool and at night they steam (due to being heated by the sun passing beneath them—Rashi).
Sanhedrin 5b
Rav said: I spent eighteen months living with a shepherd in order to know which blemishes are permanent and which are transitory.
Rav Sherira Gaon (or possibly his son, Rav Hai Gaon) Teshuvot Ha Geonim, no. 394:
Our sages were not doctors and said what they did based on experience with the diseases of their time. Therefore, there is no commandment to listen to the sages [regarding medical advice] because they only spoke from their opinion based on what they saw in their day.
Rambam, Moreh Nevuchim 3:14
Do not ask me to reconcile everything that they (the sages) stated about astronomy with the actual reality, for the science of those days was deficient, and they did not speak out of traditions from the prophets regarding these matters.
Maharam Schick, Teshuvas Maharam Schick 7
Matters that were not received by Chazal as halachah leMoshe miSinai, but rather which they said according to their own reasoning – and with something that is not received [from Sinai] and has no root in our Torah, but rather comes from investigation and experience, it is difficult to determine [that it is true]. And there are many occasions when the sages determined, according to their own intellects, that a matter was a certain way, and the subsequent generation analyzed the matter further and disputed the earlier view.
Rabbi Samson Raphael Hirsch, Trusting the Torah’s Sages, Chapter 4:
We find that Chazal themselves considered the wisdom of the gentile scholars equal to their own in the natural sciences. To determine who was right in areas where the gentile sages disagreed with their own knowledge, they did not rely on their tradition but on reason. Moreover they even respected the opinion of the gentile scholars, admitting when the opinion of the latter seemed more correct than their own.
Imagine if a scholar such as Humboldt had lived in their times and had traveled to the ends of the world for his biological investigations. If upon his return he would report that in some distant land there is a humanoid creature growing from the ground or that he had found mice that had been generated from the soil and had in fact seen a mouse that was half earth and half flesh and his report was accepted by the world as true, wouldn’t we expect Chazal to discuss the Torah aspects that apply to these instances? What laws of defilement and decontamination apply to these creatures?
Chacham Yosef Chaim, Benayahu, Bava Batra 25b
Know that regarding what R. Eliezer and R. Yehoshua say here regarding the motion of the sun, was said according to their intellectual assessment, according to whatever seemed true to them in the science of astronomy. And they did not determine these things and establish them as true; rather, each went according to whatever appeared to him in accordance with his principles of astronomy; they did not say these things as a tradition from their teachers