The energy which is expended in mere thinking, talking or writing is like the steam which escapes through the whistle of the railway engine. The whistle makes a noise, and is even interesting, but it cannot drive the engine. No amount of whistling can move the engine forward. The steam has to be harnessed and used intelligently in order that it may actually take the engine to its destination. That is why the sages have always insisted on practice rather than theory. This applies particularly to those who want to know and realize God.