Therefore by the process of self-realization or God realization through fruitive activities, philosophical speculation or mystic yoga, one cannot actually approach the supreme source of everything. When the creation is completely terminated—when there is no existence of the Vedas, no existence of material time, and no existence of the gross and subtle material elements, and when all the living entities are in the nonmanifested stage, resting within Nārāyaṇa—then all these manufactured processes become null and void and cannot act. Devotional service, however, is eternally going on in the eternal spiritual world. Therefore the only factual process of self-realization or God realization is devotional service, and one who takes to this process takes to the real process of God realization.
In this regard, Śrīla Śrīdhara Svāmī has composed a verse which conveys the idea that the supreme source of everything, the Supreme Personality of Godhead, is so great and unlimited that it is not possible for the living entity to understand Him by any material acquisition. One should therefore pray to the Lord to be engaged in His devotional service eternally, so that by the grace of the Lord one can understand the supreme source of creation. The supreme source of creation, the Supreme Lord, reveals Himself only to the devotees. In the Fourth Chapter of the Bhagavad-gītā the Lord says to Arjuna, “My dear Arjuna, because you are My devotee and because you are My intimate friend, I shall reveal to you the process of understanding Me.” In other words, the supreme source of creation, the Supreme Personality of Godhead, cannot be understood by our own endeavor. We have to please Him with devotional service, and then He will reveal Himself to us. Then we can understand Him to some extent.
There are different kinds of philosophers who have tried to understand the supreme source by their mental speculation. There are generally six kinds of mental speculators, whose speculations are called ṣaḍ-darśana. All these philosophers are impersonalists and are known as Māyāvādīs. Every one of them has tried to establish his own opinion, although they all have later compromised and stated that all opinions lead to the same goal and that every opinion is therefore valid. According to the prayers of the personified Vedas, however, none of them is valid because their process of knowledge is created within the temporary material world. They have all missed the real point: the Supreme Personality of Godhead, or the Absolute Truth, can be understood only by devotional service.
One class of philosophers, known as Mīmāṁsakas, represented by sages such as Jaimini, have concluded that everyone should engage in pious activities or prescribed duties and that such activities will lead one to the highest perfection. But this is contradicted in the Ninth Chapter of the Bhagavad-gītā, where Lord Kṛṣṇa says that by pious activities one may be elevated to the heavenly planets, but that as soon as one’s accumulation of pious activities is used up, one has to leave the enjoyment of a higher standard of material prosperity in the heavenly planets and immediately come down again to these lower planets, where the duration of life is very short and where the standard of material happiness is of a lower grade. The exact words used in the Bhagavad-gītā are kṣīṇe puṇye martya-lokaṁ viśanti (BG 9.21). Therefore the conclusion of the Mīmāṁsaka philosophers that pious activities will lead one to the Absolute Truth is not valid. Although a pure devotee is by nature inclined to perform pious activities, no one can attain the favor of the Supreme Personality of Godhead by pious activities alone. Pious activities may purify one of the contamination caused by ignorance and passion, but this purification is automatically attained by a devotee constantly engaged in hearing the transcendental message of Godhead in the form of the Bhagavad-gītā, Śrīmad-Bhāgavatam or similar scriptures. From the Bhagavad-gītā we understand that even a person who is not up to the standard of pious activities but who is absolutely engaged in devotional service is to be considered well situated on the path of spiritual perfection. It is also said in the Bhagavad-gītā that a person who is engaged in devotional service with love and faith is guided from within by the Supreme Personality of Godhead. The Lord Himself as Paramātmā, or the spiritual master sitting within one’s heart, gives the devotee exact directions by which he can gradually go back to Godhead. The conclusion of the Mīmāṁsaka philosophers is not actually the truth which can lead one to real understanding.