Originally the path of self-realization was established by the standard direction of the Vedas. Śrīla Vyāsadeva divided the original Veda into four divisions, namely Sāma, Atharva, Ṛg, and Yajur. Then he divided the same Vedas into eighteen Purāṇas (supplements) and the Mahābhārata, and then again the same author summarized them in the Vedānta-sūtras. The purpose of all these Vedic literatures is to realize one's self to be a spiritual being, eternally related with the Supreme Personality of Godhead, the all-attractive form (Śrī Kṛṣṇa).
But all these different Vedic literatures were systematically distorted by the onslaught of the age of Kali, as the walls of the paddy field and the strand of the river are distorted by the onslaught of heavy rains. The attacks of distortion are offered by atheistic philosophers who are concerned only with eating, drinking, being merry, and enjoying. These atheists are all against the revealed scriptures because such persons are intimately attached to sense pleasures and gross materialism. There are also others who do not believe in the eternity of life. Some of them propose that life is ultimately to be annihilated and that only the material energy is conserved. Others are less concerned with physical laws but do not believe anything beyond their experience. And still others equate spirit and matter and declare the distinction between them to be illusory.
There is no doubt that the Vedas stand as the most recognized books of knowledge, from every angle of vision. But over the course of time the Vedic path has been attacked by philosophers like Cārvāka, Buddha, Arhat, Kapila, Patañjali, Śaṅkara, Vaikāraṇa, Jaimini, the Nyāyakas, the Vaiśeṣikas, the Saguṇists, the empiricists, the Pāśupata Śaivas, the Saguṇa Śaivas, the Brāhmas, the Aryas, and many others (the list of non-Vedic speculators grows daily, without restriction). The path of the Vedas does not accord with any principle devoid of an eternal relation with God, attainment of His devotional service, and culmination in transcendental love for Him.