Verse 17

अनात्मन्यात्मता सैषा सैषा वस्तुन्यवस्तुता ।अविचारेण वै जाता विचारेण क्षयं गता

In plain words

"This selfhood in what is not the self, this very unreality in what is real — it was born from want of inquiry, and by inquiry it has gone to its ruin."