Here Sri Ramana not only outlines how we can discover for ourselves the truth of the world, but also he succinctly outlines the path to liberation:

If, on the contrary, you withdraw your mind completely from the world and turn it within and abide thus, that is, if you keep awake always to the Self, which is the substratum of all experience, you will find the world, of which alone you are now aware, just as unreal as the world in which you lived in your dream.

~Ramana Maharshi, Maharshi’s Gospel

The above was an excerpt taken from the following post: Ramana Maharshi: ‘…unless you give up the idea that the world is real…’

Also see Ashtavakra Gita – all is illusion, I am the Self