The impersonalists think of the Absolute Personality of Godhead in two different ways, as above mentioned. On the one hand they worship the Lord in His viśva-rūpa, or all-pervading universal form, and on the other they think of the Lord’s unmanifested, indescribable, subtle form. The theories of pantheism and monism are respectively applicable to these two conceptions of the Supreme as gross and subtle, but both of them are rejected by the learned pure devotees of the Lord because they are aware of the factual position. This is very clearly mentioned in the Eleventh Chapter of the Bhagavad-gītā, which records Arjuna’s experience of the viśva-rūpa of the Supreme Lord Śrī Kṛṣṇa:

Arjuna, as a pure devotee of the Lord, never previously saw the contemplated universal form of the Lord (viśva-rūpa), but when he did see it, his curiosities were satisfied. But he was not happy to see such a form of the Lord because of his attachment as a pure devotee. He was afraid to see the gigantic form of the Lord. He therefore prayed to the Lord to assume His four-handed Nārāyaṇa or Kṛṣṇa form, which alone could please Arjuna. Undoubtedly the Lord has the supreme potency to exhibit Himself in multifarious forms, but the pure devotees of the Lord are interested in His forms as eternally exhibited in the abode of the Lord, known as the tripād-vibhūti or kingdom of God. The Lord in the tripād-vibhūti abode exhibits Himself in two forms, either with four hands or with two hands. The viśva-rūpa exhibited in the material manifestation has unlimited hands and unlimited dimensions with everything unlimited. The pure devotees of the Lord worship Him in His Vaikuṇṭha forms as Nārāyaṇa or Kṛṣṇa. Sometimes the same Vaikuṇṭha forms of the Lord are in the material world also by His grace as Śrī Rāma, Śrī Kṛṣṇa, Śrī Narasiṁhadeva, etc., and thus the pure devotees also worship them. Usually the features shown in the material world have no existence in the Vaikuṇṭha planets, and thus they are not accepted by the pure devotees. What the pure devotees worship from the very beginning are eternal forms of the Lord existing in the Vaikuṇṭha planets. The nondevotee impersonalists imagine the material forms of the Lord, and ultimately they merge in the impersonal brahmajyoti of the Lord, whereas the pure devotees of the Lord are worshipers of the Lord both in the beginning and also in the perfect stage of salvation, eternally. The worship of the pure devotee never stops, whereas the worship of the impersonalist stops after his attainment of salvation, when he merges in the impersonal form of the Lord known as the brahmajyoti. Therefore the pure devotees of the Lord are described here as vipaścita, or the learned who are in the knowledge of the Lord perfectly.