The very reality of the world must be questioned.
Realize that whatever you think yourself to be is just a stream of events.
While all happens, comes and goes, you alone are, the changeless among the changeful, the self-evident among the inferred.
Investigate yourself and love the investigation and you will solve not only your own problems but also the problems of humanity.
Be interested in yourself beyond all experience, be with yourself, love yourself; the ultimate security is found only in self-knowledge.