Reference for Shevuot 9:15

התם דעיקר שבת הוא תני אבות ותולדות הכא דלאו עיקר שבת הוא אבות תני ותולדות לא תני

is also called knowledge. But if so, said R'Papa to Abaye, the statement in the Mishnah WHERE THERE IS NO KNOWLEDGE AT THE BEGINNING, BUT THERE IS KNOWLEDGE AT THE END [is incomprehensible, for] is there anyone who has not even the knowledge gained from a teacher?

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