De Harmonia Animæ Cum Corpore
All Things are interwoven. The most spiritual Thought in thy Soul (I speak as a Fool) is also a most material Change in Blood or Brain. Anger maketh the Blood acid; Hate poisoneth Mother's milk; even as I showed formerly in reverse, how Disturbance of physical Function altereth the States of Consciousness. Now no Man doubteth the Power of the Will of Man, whether it be his love that begetteth Children or causes wars wherein many Men be slain, whether it be his Eloquence that moveth a Mob or his Vanity that destroyeth a People. Only in all such Cases we understand how Nature worketh, through known Laws physical or psychical. That is, there is a State of unstable Equilibrium, so that one Machine setteth another in Motion as soon as the first Disturbance ariseth. Therefore, it is not proper to regard all Consequence of a Will as its Effect. Without the Revolution there could have been no great Effect of the Will of Napoleon; and moreover his Will was broken in the End, to the present Misfortune (as it seems to many beside myself) of Mankind. This Magick, therefore, dependeth greatly on the Art to set many other Wills in sympathetic Motion; and the greatest Magus may not be the most successful in a mean conception of a Limit of Time. He may need to strike many Blows before he breaketh down his Wall, if that be strong, while a Child may push over one that is ready to crumble.
 On the Haromony of the Soul with the Body