For the jñānīs, those who are seeking out the Absolute Truth by speculative knowledge, they want to make these varieties of material world as void. The Buddha philosophy, śūnyavādi. Because they are disgusted with these material varieties, therefore they want something opposite. That opposite is voidism, śūnyavāda. The śūnyavāda or, little more further, that is brahmavāda, without any varieties, simply the light, brahma-jyotir. This is also another realization. Śūnyavāda, to make this material world null and void, they come to the impersonal Brahman effulgence. This is Brahman realization.
And then, for the yogis, the localized aspect, Paramātmā. Īśvaraḥ sarva-bhūtānāṁ hṛd-deśe 'rjuna tiṣṭhati (BG 18.61). By meditation. This is Paramātmā realization. And then, ultimately, Bhagavān, the Supreme Personality of Godhead.