The most profound knowledge of God is that which recognizes the utter inadequacy of all finite conceptions, and this can only be reached by the ‘Via Negationis’, the path of the negation of all the finite.
But only a few courageous souls can face the aridity of this path from the outset, and for minds of a devotional cast the ‘Via Eminentiae’ may be more appropriate, the path in which laudable characteristics that fall within human comprehension are ascribed positively to the deity, but with the clear recognition that they are but imperfect indications of His nature, since He transcends finite comprehension.
According to a third path, the ‘Via Causalitatis’, the mind fingers, as it were, the various causal principles that it can conceive as operating in the world, and attempts to mount through speculation of this kind to some conception of the deity as the first cause, and yet as that which lies beyond any causal principle that can be determinately conceived and from which all such principles proceed as effects.
According to a fourth path, the deity is sought to be perceived as the light present within the human intellect, illuminating its knowledge of truth.
According to a fifth path, the mind tries to mount up from things that are good and desirable for some particular end to that which is itself the supreme end, lying beyond all particular ends, and which is desirable for its own sake, the highest value and supreme good
Something parallel to, though not identical with, these various paths can be found in Śaṅkara’s texts. As we have already seen, he gives preference to the path of negation and regards it as indispensible for the final knowledge which confers liberation from ignorance and death. ...How tentative, for Śaṅkara, all positive conceptions of the Absolute are.
Śaṅkara conceived the upanishadic wisdom as consisting essentially in negation. The Absolute cannot be denoted through speech, and negation is the fundamental process which leads to ‘viveka’ or discrimination of the true nature of the Self from that with which it is falsely overlaid, the highest goal of the Advaita discipline.
The process Śaṅkara has in mind is not one of brute reiterated negation but of a gradually ascending series of successive affirmations.
The texts of the Upanishads are not exclusively negative. They give many and varied positive accounts of the Absolute and of its relation to the world and the individual, which alternate with passages in which all empirically knowable qualities are denied.
The various positive accounts of the Absolute are only approximations which have the function of bringing it down, so to speak, into the universe of discourse, so that the student can acquire some idea of it which can be corrected in the light of subsequent negations.
If the opening passage of Chapter III of the second Book of the Bṛhadāraṇyaka Upanishad teaches that the five great elements that emanate from the Absolute are a reality, then the Absolute can initially be conceived as the cause from which they proceed.
But the purpose of the passage as a whole is not to teach that the Absolute is the cause of the world. The aim, rather, is to present the Absolute first in the guise of the cause of the world so as to give the student some idea of it.
When some conception of the Absolute is once in his mind, then it can be purified by the later text ‘Not thus, not thus’, which negates all empirically knowable characteristics of the Absolute, including that of being the cause of the world.
As we have already seen, Śaṅkara did not invent this method of interpreting the texts, but inherited it from earlier Teachers such as Gauḍapāda and Draviḍa. It is known as the method of false attribution and subsequent denial (adhyāropa and apavāda).
~Alston, Absolute, 165