Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 18

Sanskrit:

ज्ञानं विवेको निगमस्तपश्चप्रत्यक्षमैतिह्यमथानुमानम् ।आद्यन्तयोरस्य यदेव केवलंकालश्च हेतुश्च तदेव मध्ये ॥ १८ ॥

ITRANS:

jñānaṁ viveko nigamas tapaś capratyakṣam aitihyam athānumānamādy-antayor asya yad eva kevalaṁkālaś ca hetuś ca tad eva madhye

Translation:

Real spiritual knowledge is based on the discrimination of spirit from matter, and it is cultivated by scriptural evidence, austerity, direct perception, reception of the Purāṇas’ historical narrations, and logical inference. The Absolute Truth, which alone was present before the creation of the universe and which alone will remain after its destruction, is also the time factor and the ultimate cause. Even in the middle stage of this creation’s existence, the Absolute Truth alone is the actual reality.

Purport:

Material scientists and philosophers are desperately searching for the ultimate material cause or principle, which is described here as kāla, the time factor. The material process of cause and effect takes place entirely within a sequence of time; in other words, the time factor is the motivating impetus for material cause and effect. This time factor is a manifestation of the Supersoul, the form of the Supreme Lord that pervades and supports the cosmic manifestation. The method for acquiring knowledge is scientifically described here, and those who are serious, reasonable scholars will take advantage of the transcendental epistemology revealed here by the Lord.