One who acts on the mental platform has to change his standard of knowledge periodically. We consequently see that one philosopher may disagree with another philosopher, and one scientist may put forward a theory contradicting the theory of another scientist. All of this is due to their working on the mental platform without a standard of knowledge. In the Vedic instructions, however, the standard of knowledge is accepted, even though it may sometimes appear that the statements are contradictory. Because the Vedas are the standard of knowledge, even though they may appear contradictory, they should be accepted. If one does not accept them, he will be bound by the material conditions.