'Διαφέρομεν δὲ καὶ ταῖς τῶν πολεμικῶν μελέταις τῶν ἐναντίων τοῖσδε. τήν τε γὰρ πόλιν κοινὴν παρέχομεν, καὶ οὐκ ἔστιν ὅτε ξενηλασίαις ἀπείργομέν τινα ἢ μαθήματος ἢ θεάματος, ὃ μὴ κρυφθὲν ἄν τις τῶν πολεμίων ἰδὼν ὠφεληθείη, πιστεύοντες οὐ ταῖς παρασκευαῖς τὸ πλέον καὶ ἀπάταις ἢ τῷ ἀφ' ἡμῶν αὐτῶν ἐς τὰ ἔργα εὐψύχῳ· καὶ ἐν ταῖς παιδείαις οἱ μὲν ἐπιπόνῳ ἀσκήσει εὐθὺς νέοι ὄντες τὸ ἀνδρεῖον μετέρχονται, ἡμεῖς δὲ ἀνειμένως διαιτώμενοι οὐδὲν ἧσσον ἐπὶ τοὺς ἰσοπαλεῖς κινδύνους χωροῦμεν. τεκμήριον δέ· οὔτε γὰρ Λακεδαιμόνιοι καθ' ἑαυτούς, μεθ' ἁπάντων δὲ ἐς τὴν γῆν ἡμῶν στρατεύουσι, τήν τε τῶν πέλας αὐτοὶ ἐπελθόντες οὐ χαλεπῶς ἐν τῇ ἀλλοτρίᾳ τοὺς περὶ τῶν οἰκείων ἀμυνομένους μαχόμενοι τὰ πλείω κρατοῦμεν. ἁθρόᾳ τε τῇ δυνάμει ἡμῶν οὐδείς πω πολέμιος ἐνέτυχε διὰ τὴν τοῦ ναυτικοῦ τε ἅμα ἐπιμέλειαν καὶ τὴν ἐν τῇ γῇ ἐπὶ πολλὰ ἡμῶν αὐτῶν ἐπίπεμψιν· ἢν δέ που μορίῳ τινὶ προσμείξωσι, κρατήσαντές τέ τινας ἡμῶν πάντας αὐχοῦσιν ἀπεῶσθαι καὶ νικηθέντες ὑφ' ἁπάντων ἡσσῆσθαι. καίτοι εἰ ῥᾳθυμίᾳ μᾶλλον ἢ πόνων μελέτῃ καὶ μὴ μετὰ νόμων τὸ πλέον ἢ τρόπων ἀνδρείας ἐθέλομεν κινδυνεύειν, περιγίγνεται ἡμῖν τοῖς τε μέλλουσιν ἀλγεινοῖς μὴ προκάμνειν, καὶ ἐς αὐτὰ ἐλθοῦσι μὴ ἀτολμοτέρους τῶν αἰεὶ μοχθούντων φαίνεσθαι, καὶ ἔν τε τούτοις τὴν πόλιν ἀξίαν εἶναι θαυμάζεσθαι καὶ ἔτι ἐν ἄλλοις.
"If we turn to our military policy, there also we differ from our antagonists. We throw open our city to the world, and never by alien acts exclude foreigners from any opportunity of learning or observing, although the eyes of an enemy may occasionally profit by our liberality; trusting less in system and policy than to the native spirit of our citizens; while in education, where our rivals from their very cradles by a painful discipline seek after manliness, at Athens we live exactly as we please, and yet are just as ready to encounter every legitimate danger. In proof of this it may be noticed that the Lacedaemonians do not invade our country alone, but bring with them all their confederates; while we Athenians advance unsupported into the territory of a neighbour, and fighting upon a foreign soil usually vanquish with ease men who are defending their homes. Our united force was never yet encountered by any enemy, because we have at once to attend to our marine and to dispatch our citizens by land upon a hundred different services; so that, wherever they engage with some such fraction of our strength, a success against a detachment is magnified into a victory over the nation, and a defeat into a reverse suffered at the hands of our entire people. And yet if with habits not of labour but of ease, and courage not of art but of nature, we are still willing to encounter danger, we have the double advantage of escaping the experience of hardships in anticipation and of facing them in the hour of need as fearlessly as those who are never free from them. Nor are these the only points in which our city is worthy of admiration."
This series of qualities can be understood literally, as an assertion that the Athenians were, in fact, different from other peoples, that even after taking their ease, and pursuing a free life of pleasure, and keeping their city open to one and all, they were still just as hardy and war-ready as their Spartan antagonists, whose whole existence was famously one of training and hardship.
On the other hand--and we have to consider this in light of Thucydides' presumed knowledge of the outcome of the war--this might be a stinging example of Athenian hybris, an asserted "exceptionalism" that didn't in fact live up to its promise in the end. I am just old enough to remember stirring reminders that Americans don't lose wars, and there's some of that asserted superiority here, the pride the goeth before a fall. There is especially that claim to "courage not of art but of nature," "μὴ μετὰ νόμων τὸ πλέον ἢ τρόπων ἀνδρείας ," that asserts what is normally a hard-won virture as a birthright: "Land of the free and home of the brave."
It's painful to read a passage like this because, if anywhere, there is real justification for talking about an Athenian "exceptionalism." The explosion of art and reflection that burst onto the scene among these fifth century Greeks came to change all of humanity. It was an extraordinarily creative period that arguably was without precedent. And surely there must have been some awareness among them of that unprecedented expansion of human possibilities.
But they were not gods--not even gods as the Greeks conceived them--and the most self-aware historians and dramatists and philosophers were not slow to make that point as well. Something made the Athenians exceptional. But it was not "nature." They were human, sharing the same nature with Spartans, the same nature even with "barbarians," with those who couldn't even speak Greek.
It is the custom of demagogues to praise the peoples' virtues. Aristocrats--of power, of wealth, or of the mind--tend to think somewhat less of the "mob." This is one of those examples where, if this is an accurate rendition of the speech, the import of Pericles' words might have had one meaning for himself, another for his listeners, and a third for Thucydides.