Srimad-Bhagavatam: Canto 3 - Chapter 1 - Verse 27


वैकारिकाद्विकुर्वाणान्मनस्तत्त्वमजायत ।यत्सङ्कल्पविकल्पाभ्यां वर्तते कामसम्भव: ॥ २७ ॥


vaikārikād vikurvāṇānmanas-tattvam ajāyatayat-saṅkalpa-vikalpābhyāṁvartate kāma-sambhavaḥ


From the false ego of goodness, another transformation takes place. From this evolves the mind, whose thoughts and reflections give rise to desire.


The symptoms of the mind are determination and rejection, which are due to different kinds of desires. We desire that which is favorable to our sense gratification, and we reject that which is not favorable to sense gratification. The material mind is not fixed, but the very same mind can be fixed when engaged in the activities of Kṛṣṇa consciousness. Otherwise, as long as the mind is on the material platform, it is hovering, and all this rejection and acceptance is asat, temporary. It is stated that he whose mind is not fixed in Kṛṣṇa consciousness must hover between acceptance and rejection. However advanced a man is in academic qualifications, as long as he is not fixed in Kṛṣṇa consciousness he will simply accept and reject and will never be able to fix his mind on a particular subject matter.