Verse 17

मृगतृष्णा यथा तापान्मनसो निश्चयात्तथा ।असन्त इव दृश्यन्ते सर्वे ब्रह्मादयोऽप्यमी

In plain words

As a mirage arises from heat, so from the mind's own conviction all these, even Brahmā and the rest, unreal, are seen as it were.