O Fabricius! What would your great soul have thought, if to your own misfortune you had been called back to life and had seen the pompous face of this Rome saved by your efforts and which your honourable name had distinguished more than all its conquests? 'Gods,' you would have said, 'what has happened to those thatched roofs and those rustic dwelling places where, back then, moderation and virtue lived? What fatal splendour has succeeded Roman simplicity? What is this strange language? What are these effeminate customs? What do these statues signify, these paintings, these buildings? You mad people, what have you done? You, masters of nations, have you turned yourself into the slaves of the frivolous men you conquered? Are you now governed by rhetoricians? Was it to enrich architects, painters, sculptors, and comic actors that you soaked Greece and Asia with your blood? Are the spoils of Carthage trophies for a flute player? Romans, hurry up and tear down these amphitheatres, break up these marbles, burn these paintings, chase out these slaves who are subjugating you, whose fatal arts are corrupting you. Let other hands distinguish themselves with vain talents. The only talent worthy of Rome is that of conquering the world and making virtue reign there. When Cineas took our Senate for an assembly of kings, he was not dazzled by vain pomp or by affected elegance. He did not hear there this frivolous eloquence, the study and charm of futile men. What then did Cineas see that was so majestic? O citizens! He saw a spectacle which your riches or your arts could never produce, the most beautiful sight which has ever appeared under heaven, an assembly of two hundred virtuous men, worthy of commanding in Rome and governing the earth.
What happened? It took Gibbon six volumes to describe the decline and fall of the Roman Empire, so I shan’t embark on that. But thinking about this almost incredible episode does tell one something about the nature of civilisation. It shows that however complex and solid it seems, it is actually quite fragile. It can be destroyed. 

What are its enemies?

Well, first of all fear — fear of war, fear of invasion, fear of plague and famine, that make it simply not worthwhile constructing things, or planting trees or even planning next year’s crops. And fear of the supernatural, which means that you daren’t question anything or change anything. The late antique world was full of meaningless rituals, mystery religions, that destroyed self-confidence. And then exhaustion, the feeling of hopelessness which can overtake people even with a high degree of material prosperity. 

There is a poem by the modern Greek poet, Cavafy, in which he imagines the people of an antique town like Alexandria waiting every day for the barbarians to come and sack the city. Finally the barbarians move off somewhere else and the city is saved; but the people are disappointed — it would have been better than nothing. Of course, civilisation requires a modicum of material prosperity—

What civilization needs:

confidence in the society in which one lives, belief in its philosophy, belief in its laws, and confidence in one’s own mental powers. The way in which the stones of the Pont du Gard are laid is not only a triumph of technical skill, but shows a vigorous belief in law and discipline. Vigour, energy, vitality: all the civilisations—or civilising epochs—have had a weight of energy behind them. People sometimes think that civilisation consists in fine sensibilities and good conversations and all that. These can be among the agreeable results of civilisation, but they are not what make a civilisation, and a society can have these amenities and yet be dead and rigid.