a. 不可认识的, 不可知的, 不可辨别的

[ adj ]
incapable of being perceived or known
<adj.all>

Incognizable \In*cog"ni*za*ble\, a.
Not cognizable; incapable of being recognized, known, or
distinguished. --H. Spenser.

The Lettish race, not a primitive stock of the Slavi,
but a distinct branch, now become incognizable.
--Tooke.