But monism denies all justification to metaphysics, which merely draws inferences, and consequently also to the impulses of action which are derived from so-called "Beings-in-themselves". According to the monistic view, man may act unfreely-when he obeys some perceptible external compulsion; he can act freely, when he obeys none but himself. Monism cannot recognize any unconscious compulsion hidden behind percept and concept. If anyone asserts that the action of a fellow man is done unfreely, then he must identify the thing or the person or the institution within the perceptible world, that has caused the person to act; and if he bases his assertion upon causes of action lying outside the world that is real to the senses and the spirit, then monism can take no notice of it.