{Reason} is a very good instrument for all ethics, morality, self-control, but spiritual life goes beyond these things and reason understands nothing of it.
…If it tries to intervene it is an obstacle, if it withdraws in an orderly way and' remains quiet, then it is very good.
It is an obstacle if you want to use it as judge and master. But it is not an obstacle if you use it as an instrument, like all the other parts of the being. It is an excellent instrument on condition that it remains an instrument and does not want to become the master who decides and judges. It is a power of judgment which, in its field, is absolutely right. But as soon as it goes beyond its domain, it cannot understand, it has no discernment any longer.
So if the reason understands this and keeps quiet, with the attitude of an instrument and not of master and judge, it is perfect.