It is possible to say that man is like a “black box” which feels and understands and receives only that which comes from outside . In all of our investigations, we are limited by our five senses. And all of the instruments which we build, and which are to be built in the future, do not escape the limitations of our five senses. They merely widen the boundaries of our senses.

This is because we are never able to imagine what our senses lack. Namely, what other additional sense we need in order to recognize the true reality around us. We feel no lack for this, as we feel no lack of a sixth finger on our hands. That for which we feel no lack, can never be something to which we would come to request. Therefore, all of the investigations of our world are only according to our five senses, and we can never begin to see and feel and understand what is beyond our senses. These are the limitations of our conceptions.

Courtesy of http://www.youtube.com/watch?v=umw1-Do3-ho