I don’t think anybody will deny that it’s possible (maybe probable) that in general great Rabbis are smarter/have better insight. The issue is how this applies to individual issues that might be beyond the scope of Rabbinic expertise, or something in which they may not have all the information. The issue then becomes whether there can be a “psak” in non-halachic issues (unless you say that every issue is a halachic issue). In that regard see the Rambam peirush hamishnayos Sotah 3:5, Sanhedrin 10:3, Shavuos 1:4, Sefer Hamitzvos Lo Saaseh 133, Maamar Techias Hameisim, and R’ Shmuel Hanagid’s Mavo Hatalmud (the last line) for a start.
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