Peter Attia· MD
and math science knowledge is hierarchical right and this is back to mastery which is we've why we do poorly we've given up mastery in this country why um we're a timebased system right at the end of third grade you're moving to fourth grade and at the end of fourth grade you're moving to fifth grade and we don't hold kids back we don't we just we've said we're just going to move kids through no matter what