Ashtavakra Gita 18.38 -

Remember: human personality is a composite. It is more invisible and internal, than visible and external. Our body is limited, senses even more so. Mind, unphysical and internal, alone employs the senses, perceives the world and gives shape to the perceptions.

Enormity of sensory perceptions is verily to be attributed to the power and potential of the inner mind. Is not then the inner probe indispensable and rewarding for the human? Once you begin the inner enquiry, the whole picture is bound to change. The noumenon, not the phenomena outside, will become paramount. The ignorant refuse to do this, and hence indulge in external pleasures only, which corrode and exhaust us day after day.

The discreet are given to examine, evaluate matters with intelligence. Life is not sensory alone for them. It is more mental and intelligential. However colourful and manifold objects may seem, they are fleeting to the core. This one truth takes away all its charm. Thus, to foster desire for external things is calamitous.

Consequently, the wise begin to probe into their own within, only to find that externality is itself like mirage on the desert. Mind is the root cause of it all. All perceptions belong to the inner mind. Outer phenomena are but an extension from the mind. When mind leaves its desiring habit, the whole world becomes extinct. The wise thus exterminate the whole world.