Emptiness is not something like just remaining there without having thoughts or anything at all. It is said in the scriptures that if one does not know how to meditate properly on emptiness, then one can fall into the wrong way. To correctly establish the ultimate nature as emptiness, investigate the true nature of mind. Maintain this through the practice of meditation.
Emptiness which is merely empty and the emptiness which is the nature of mind are different. The first emptiness is just nothingness. This kind of emptiness is shown by the example of ‘the horns of a rabbit’. It is just not there. But the emptiness of the mind is different. It does not have any form, colour or shape. It is not existent, and at the same time, it is everything. It is that which creates all of Samsara and Nirvana.
From Kyabje Penor Rinpoche’s teaching given on 12th November 1999