It is necessary to insist on this point, that the metaphysical domain lies entirely outside the phenomenal world, for the moderns hardly ever know or investigate anything other than phenomena; it is with these that they are almost exclusively concerned, as is demonstrated by the attention they have given to the experimental sciences. Their metaphysical ineptitude arises from the same tendency. Undoubtedly some phenomena may occur during the work for metaphysical realization, but in a quite accidental manner. They can also have unfortunate consequences, as things of this nature are only an obstacle for those who are tempted to attach importance to them. Those who are halted or turned aside by phenomena, and above all those who indulge in search for extraordinary "powers," have very little chance of pressing on to a realization beyond the point already arrived at before this deviation occurred. Essays: Oriental Metaphysics