Why should we think there's some--Even though, normally, the barrier can be crossed and Xs can study the non-X, why should that barrier suddenly become un-crossable in the particular instance when we're dealing with Platonic forms?

为什么我们应该认为即使通常来说,那个界限是可以跨越的,即X可以研究非X,那为什么这个界限突然,在讨论柏拉图型相的时候,就变得不可逾越了呢

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