The first way is the way of the Fakir. It is a long, difficult and uncertain way. A fakir works on the physical body, on conquering physical pain.
The second way is the way of the Monk. This way is shorter, more sure and definite. It requires certain conditions, but above all it requires faith, for if there is no faith a man cannot be a true monk.
The third way is the way of the Yogi, the way of knowledge and consciousness .... When we speak of yogis we really take only Jnana-Yoga and Raja-Yoga. Jnana-Yoga is the yoga of knowledge, of a new way of thinking. It teaches to think in different categories, not in categories of space and time and of causality. And Raja-Yoga is work on being, on consciousness.
Although in many respects these ways are very efficient, the characteristic thing about them is that the first step is the most difficult. From the very first moment you have to give up everything and do what you are told. If you keep one little thing, you cannot follow any of these ways. So, although the three ways are good in many other respects, they are not sufficiently elastic.
....Then in the Fourth Way the first principle is that man must not believe in anything; he must learn; so faith does not enter into the Fourth Way. One must not believe what one hears or what one is advised, one must find proofs for everything. If one is convinced that something is true, then one can believe it, but not before. [pp.97-98]
Source: The Fourth Way (Vintage)
Contributed by: beyourownmedicine