3.42 The senses are called the important obstacles of knowledge, because when the senses keep operating on their objects, the knowledge of the self cannot arise. 'The mind is higher than the senses':  even if the senses are withdrawn, if the Manas (mind) ruminates over sense objects, knowledge of the self cannot be had. 'The intellect (Buddhi) is greater than the mind', i.e., even if the mind is indifferent to sense objects, a perverted decision by the intellect can obstruct the dawn of the knowledge of the self. But even if all of them upto the intellect are ietened from their activity, still when desire, identified with will, originating from Rajas, is operating, it by itself obstructs the knowledge of the self by inducing the senses etc., to operate in their fields. Thus it is said here:  'But what is greater than intellect is that.' What is greater than the intellect - is desire. Such is the sense of the last sentence here.