Such are our Jacobins， born out of social decomposition like mushrooms out of compost. Let us consider their inner organization， for they have one as formerly the Puritans； we have only to follow their dogma down to its depths， as with a sounding-line， to reach the psychological stratum in which the normal balance of faculty and sentiment is overthrown.
When a statesman， who is not wholly unworthy of that great name， finds an abstract principle in his way， as， for instance， that of popular sovereignty， he accepts it， if he accepts it at all， according to his conception of its practical bearings. He begins， accordingly， by imagining it applied and in operation. From personal recollections and such information as he can obtain， he forms an idea of some village or town， some community of moderate size in the north， in the south， or in the center of the country， for which he has to make laws. He then imagines its inhabitants acting according to his principle， that is to say， voting， mounting guard， levying taxes， and administering their own affairs. Familiar with ten or a dozen groups of this sort， which he regards as examples， he concludes by analogy as to others and the rest on the territory. Evidently it is a difficult and uncertain process； to be exact， or nearly so， requires rare powers of observation and， at each step， a great deal of tact， for a nice calculation has to be made on given quantities imperfectly ascertained and imperfectly noted！[15] Any political leader who does this successfully， does it through the ripest experience associated with genius. And even then he keeps his hand on the check-rein in pushing his innovation or reform； he is almost always tentative； he applies his law only in part， gradually and provisionally； he wishes to ascertain its effect； he is always ready to stay its operation， amend it， or modify it， according to the good or ill results of experiment；the state of the human material he has to deal with is never clear to his mind， even when superior， until after many and repeated gropings.
-- Now the Jacobin pursues just the opposite course. His principle is an axiom of political geometry， which always carries its own proof along with it； for， like the axioms of common geometry， it is formed out of the combination of a few simple ideas， and its evidence imposes itself at once on all minds capable of embracing in one conception the two terms of which it is the aggregate expression. Man in general， the rights of Man， the social contract， liberty， equality， reason， nature， the people， tyrants， are examples of these basic concepts： whether precise or not， they fill the brain of the new sectarian. Often these terms are merely vague and grandiose words， but that makes no difference； as soon as they meet in his brain an axiom springs out of them that can be instantly and absolutely applied on every occasion and to excess. Mankind as it is does not concern him. He does not observe them； he does not require to observe them； with closed eyes he imposes a pattern of his own on the human substance manipulated by him； the idea never enters his head of forming any previous conception of this complex， multiform， swaying material - contemporary peasants， artisans， townspeople， curés and nobles， behind their plows， in their homes， in their shops， in their parsonages， in their mansions， with their inveterate beliefs， persistent inclinations， and powerful wills.
Nothing of this enters into or lodges in his mind； all its avenues are stopped by the abstract principle which flourishes there and fills it completely. Should actual experience through the eye or ear plant some unwelcome truth forcibly in his mind， it cannot subsist there； however noisy and relentless it may be， the abstract principle drives it out；[16] if need be it will distort and strangle it， considering it a slanderer since it refutes a principle which is true and undeniable in itself. Obviously， a mind of this kind is not sound； of the two faculties which should pull together harmoniously， one is degenerated and the other overgrown； facts cannot turn the scale against the theory. Charged on one side and empty on the other， the Jacobin mind turns violently over on that side to which it leans， and such is its incurable infirmity.