Mental Speculation Is Not Spiritual - Prabhupada - 0337
761009 - Lecture SB 01.02.05 - Aligarh
The modern scientist or philosophers, they are engaged in studying this inferior nature. They have no information of the superior nature. But Kṛṣṇa says that these eight elements: five gross and three subtle. The mind is also material. Khaṁ mano buddhir. These are material. People think this mental speculation, poetry, philosophy, that is spiritual. No. So long the subject matter is material, the concoction of the mind, speculation of the mind, the so-called philosophy, is also material.
When mind is engaged at the lotus feet of the Lord sa vai manaḥ kṛṣṇa-padāravindayor (SB 9.4.18). When the mind is fixed up in the lotus feet of the Lord, then the words are used, the vibration of the tongue used . . . vacāṁsi vaikuṇṭha-guṇānuvarṇane. Then the words are utilized for describing about the spiritual world.