In modern times, certain people who claim to be Vedāntins, say that you should first gain indirect knowledge of ātmā from the śruti and then you should 'realise' that ātmā. In fact, there is no ātmā to realise; there is only you—tat tvam asi. The śruti does not say that you have to 'realise' Brahman, but that you are Brahman, which is an entirely different thing. But then, these modem Vedāntins will say that there is an ātmā which is all bliss and which you have to realise. That is not how it is.
The śruti says that there is a cause of creation, called Brahman, and that Brahman is this ātmā, the self–evident 'I'. Knowledge, jñāna, of that has to be immediate knowledge; it can never be indirect. Some people say that initially one gains an indirect knowledge in the form of the understanding: 'There is an entity called Brahman, which is the cause of this world.' They call this parokṣa–jñāna. And they say, later, one has to realise that Brahman as oneself. This, they say, is aparokṣa–jñāna. But this is not very correct.
If I understand only the fact that Brahman exists, though one may call it indirect knowledge, parokṣa–jñāna, it is really only śraddhā. Some logic is given, no doubt, but still, Brahman is not understood because Brahman is ātmā, myself, and that being so, how will I understand Brahman indirectly as an object? There is no object called Brahman, nor is there any understanding of Brahman other than ātmā.
If Brahman is just known as a word that means the cause of creation, that is not really knowledge but simple śraddhā, just like a belief in the existence of heaven. The difference between these two beliefs is that I have to find out later whether heaven exists or not; but since the world is Brahman right now, by understanding that, I can know Brahman right now. When I say that I don't understand how the world is Brahman, that I see only the world but not Brahman, it is still śraddhā. Even if I say that Brahman is the cause and this world is the effect, I have some more understanding about it, but not real knowledge, jñāna, because Brahman happens to be myself. Therefore, this knowledge has to be converted into immediate knowledge, aparokṣa–jñāna, of myself as Brahman.
Then, if in spite of having this knowledge, there is some doubt about myself or I believe just the opposite about myself, this viparīta–bhāvana has to be taken care of by analysis, manana. And if there is an habitual error that makes me take myself to be other than Brahman, in spite of clear knowledge, that has to be removed by contemplation, nididhyāsana. This will make the knowledge clear and free of doubt, vagueness, error, and any habitual orientation that is opposed to the knowledge. This clear knowledge is called vijñāna. This is the distinction between jñāna and vijñāna with reference to ātmā.‘Bhagavad Gita Home Study Course’ Ch.18 v42, Swami Dayananda © Copyright Arsha Vidya 2018