You may be Christian, you may be Hindu, you may be dark, you may be white, whatever is there, you have got a particular type of duty. Nobody is without any occupation. Everyone is engaged some sort of duty. The storekeeper is engaged in his business, the factory man is engaged in his business, the lawyer is engaged in his business. Everyone.
So Sūta Gosvāmī said, ataḥ pumbhir dvija-śreṣṭhā varṇāśrama-vibhāgaśaḥ. There are different kinds of duties according to the different division of the human society. That is a fact. Nobody can deny it. But how one can understand that the duty he is performing is successful? How one can understand? What is the test? You may be whatever you are doing, that doesn't matter. But how it is tested, that whatever you have done in your whole life, it has become successful.
The test is, according to Bhāgavatam, svanuṣṭhitasya dharmasya. Everyone's duty, the point of perfection is saṁsiddhir hari-toṣaṇam (SB 1.2.13), whether by your duty you have satisfied the Supreme Personality of Godhead. That is the duty. Then it is perfect. You are a great scientist? Very good. But if you can prove scientifically that there is God, that is successful. Otherwise, it is nonsense.
If you prove that there is no God, God is dead by scientific method, it is simply lunacy, craziness. That's all. Similarly, if you are philosopher, very expert in mental speculation and writing volumes of books, speculative, but if you can prove that there is God, then your philosophy is perfect—any line you take.