People often think that they have understood Brahman fully. But, it is really immeasurable and unfathomable. To drive home this point, Sri Ramakrishna used to narrate a beautiful story.
Once, an ant went to a sugar hill. It had gone there with the idea of eating up the entire hill, but one grain filled its stomach. Taking another grain in its mouth it started on its onward journey. On its way it thought, “Next time I shall carry home the whole hill”. How ridiculous and shallow is its understanding ! That is the way shallow minds think. They do not know that Brahman is beyond words and thought. However, great a man may be, still he cannot say that he has known Brahman completely. Even great sages like Sukadeva may at best be like big ants. Even they at the most could carry eight or ten grains of sugar.
Why is the knowledge of Brahman so difficult to attain? That is because all our knowledge and all our experiences are within the domain of the senses, but Brahman which is super sensuous knowledge is beyond words, intellect and minds. That is why one of the traditional methods of Sadhana advocated for attaining the knowledge of Brahman is the path of ‘Neti Neti’ or ‘Not this, Not this’. In this method all that is experienced is negated as non-Brahman till the true knowledge of Brahman dawns on the Sadhaka or practitioner. Such a knowledge is of a transcendental nature and is beyond the senses. Then the Sadhaka or practitioner neither affirms nor denies his attainment of the knowledge of Brahman. He virtually becomes speechless. But, his very face shines with a special glow or lustre leaving no room for any doubt, in the minds of seekers who approach such a person.