Our eyes are imperfect, our all senses are imperfect. We gather knowledge by the sense, five knowledge-gathering senses and five working senses and mind. So if the senses are imperfect, then how can I gather real knowledge? And without getting real knowledge, if I preach, that is cheating. Just like so many scientists, philosophers, they are cheating. Actually they have no knowledge that life cannot be produced by chemical combination; still, they are cheating people throughout the whole world that life can be produced by chemical combination. And this cheating is accepted.
Lecture on Bhagavad-gita 7.2, Nairobi, 28 October, 1975