Gustave Le Bon

Taken separately, the men of the Convention were enlightened citizens of peaceful habits. United in a crowd, they did not hesitate to give their adhesion to the most savage proposals, to guillotine individuals most clearly innocent, and, contrary to their interests, to renounce their inviolability and to decimate themselves.

All depends on the nature of the suggestion to which the crowd is exposed.

Doubtless a crowd is often criminal, but also it is often heroic.