The new sociologists call it the herd instinct, just as the old reactionaries called it the many-headed beast.

But both agree in implying that it is hardly worth while to count how many head there are of such cattle.
In face of such fashionable comparisons it will seem comparatively mild to talk of migration as it occurs among birds or insects.
Nevertheless we may venture to state with some confidence that both the sociologists and the reactionaries are wrong.
It does not follow that human beings become less than human because their ideas appeal to more and more of humanity.

Nor can we deduce that men are mindless solely from the fact that they are all of one mind.
In plain fact the virtues of a mob cannot be found in a herd of bulls or a pack of wolves, any more than the crimes of a mob can be committed by a flock of sheep or a shoal of herrings.
Birds have never been known to besiege and capture an empty cage of an aviary, on a point of principle, merely because it had kept a few other birds in captivity, as the mob besieged and captured the almost empty Bastille, merely because it was the fortress of a historic tyranny.
And rats have never been known to die by thousands merely in order to visit a particular trap in which a particular rat had perished, as the poor peasants of the First Crusade died in thousands for a far-off sight of the Sepulchre or a fragment of the true cross.
In this sense indeed the Crusade was not rationalistic, if the rat is the only rationalist.

But it will seem more truly rational to point out that the inspiration of such a crowd is not in such instincts as we share with the animals, but precisely in such ideas as the animals never (with all their virtues) understand.
What is peculiar about the First Crusade is that it was in quite a new and abnormal sense a popular movement.

I might almost say it was the only popular movement there ever was in the world.
For it was not a thing which the populace followed; it was actually a thing which the populace led.