There is a thought that stops thought. That is the only thought that ought to be stopped. That is the ultimate evil against which all religious authority was aimed. It only appears at the end of decadent ages like our own: and already Mr. H.G.Wells has raised its ruinous banner; he has written a delicate piece of scepticism called "Doubts of the Instrument." In this he questions the brain itself, and endeavours to remove all reality from all his own assertions, past, present, and to come. But it was against this remote ruin that all the military systems in religion were originally ranked and ruled. The creeds and the crusades, the hierarchies and the horrible persecutions were not organized, as is ignorantly said, for the suppression of reason. They were organized for the difficult defence of reason. Man, by a blind instinct, knew that if once things were wildly questioned, reason could be questioned first. The authority of priests to absolve, the authority of popes to define the authority, even of inquisitors to terrify: these were all only dark defences erected round one central authority, more undemonstrable, more supernatural than all--the authority of a man to think. We know now that this is so; we have no excuse for not knowing it. For we can hear scepticism crashing through the old ring of authorities, and at the same moment we can see reason swaying upon her throne. In so far as religion is gone, reason is going. For they are both of the same primary and authoritative kind. They are both methods of proof which cannot themselves be proved. And in the act of destroying the idea of Divine authority we have largely destroyed the idea of that human authority by which we do a long-division sum. With a long and sustained tug we have attempted to pull the mitre off pontifical man; and his head has come off with it. Lest this should be called loose assertion, it is perhaps desirable, though dull, to run rapidly through the chief modern fashions of thought which have this effect of stopping thought itself. Materialism and the view of everything as a personal illusion have some such effect; for if the mind is mechanical, thought cannot be very exciting, and if the cosmos is unreal, there is nothing to think about. But in these cases the effect is indirect and doubtful. In some cases it is direct and clear; notably in the case of what is generally called evolution.