Philosophy is not a mental speculation. Philosophy is the prime science from which all other sciences are derived. That is philosophy. So our Kṛṣṇa consciousness movement is trying to educate people on this science of sciences to understand first of all that "What you are? Are you this body or different from this body?" This is essential. And if you go on constructing your big building on a defective foundation, then it will not stay. There will be danger. So modern civilization is based on this defective idea that "I am this body." "I am Indian," "I am American," "I am Hindu," "I am Muslim," "I am Christian"—these are all bodily concept of life. "Because I have got this body from a Christian father and mother, therefore I am a Christian." But I am not this body. "Because I have got this body from a Hindu father and mother, therefore I am Hindu." But I am not this body. So for spiritual understanding, this is the basic principle to understand, that "I am not this body; I am soul," ahaṁ brahmāsmi. This is the Vedic instruction: "Try to understand that you are spirit soul; you are not this body." The yoga system is practiced just to understand this. Yoga indriya saṁyamaḥ. By controlling the senses, especially the mind... Mind is the master or the chief of the senses. Manaḥ-ṣaṣṭhānīndriyāṇi prakṛti-sthāni karṣati (BG 15.7). We are undergoing a struggle for existence with this mind and the senses under the false conception of identifying this body as self. So if we concentrate our mind by controlling the senses, then we can gradually understand. Dhyānāvasthita-tad-gatena manasā paśyanti yaṁ yoginaḥ (SB 12.13.1). The yogis, they meditate upon the Supreme Person, Viṣṇu, and by that process they realize the self. Self-realization is the prime object of human life. So the beginning of self-realization is to understand that "I am not this body; I am spirit soul." Ahaṁ brahmāsmi.
So these things are very nicely explained in the Bhagavad-gītā. If we simply read Bhagavad-gītā carefully, under proper guidance, then everything will be clear, without any difficulty, that "I am not this body, I am spirit soul. My business is different than this bodily concept of life. I shall never be happy taking, accepting this body as self. That is a wrong foundation of knowledge." In this way, if we make progress, then we shall understand, ahaṁ brahmāsmi: "I am spirit soul." Then wherefrom I have come? Everything is described in the Bhagavad-gītā, that the spirit soul, Kṛṣṇa says, the Lord says, mamaivāṁśo jīva-bhūtaḥ: (BG 15.7) "These living entities, they are My part and parcel, fragment, or minute sparks." As the big fire and the small fire, both of them are fire, but big fire and small fire... So far the fire quality is concerned, God and we are the same. So we can understand, we can study God by studying ourselves. That is another meditation. But it will be perfect when we understand that "Although qualitatively I am a sample of God or the same quality, but still, He is the great, I am the small." That is perfect understanding. Anu, vibhu; Brahman, Para-brahman; īśvara, parameśvara—this is perfect understanding. Because I am qualitatively one, it does not mean that I am the Supreme. In the Vedas it is said, nityo nityānāṁ cetanaś cetanānām (Kaṭha Upaniṣad 2.2.13). We are nitya, eternal; God is also eternal. We are living being; God is also a living being. But He is the chief living being; He is the chief eternal. We are also eternal, but we are not chief. Why? Eko yo bahūnāṁ vidadhāti kāmān. Just like we require a leader, similarly, He is the supreme leader. He is maintainer. He is providence. He is providing everyone's necessities. We can see that there are elephants in Africa. Who is providing them food? There are millions of ants within the hole of your room. Who is feeding them? Eko yo bahūnāṁ vidadhāti kaman. So in this way, if we realize ourself, that is self-realization.