The Greeks had a secret weapon. They used it to huge advantage and with devastating purpose against their enemies. Called Greek fire, it still remains somewhat of a mystery. What little is known is that it consisted of crude oil mixed with resin. Projected through a hydraulic pipe it set enemy ships instantly ablaze.

It was the napalm bomb of its day. It was so uniquely effective that in the 10th century the Byzantine emperor Constantine VII listed it as a state secret. Effective as Greek fire was, it proved ephemeral. Unable to prevent the fall of Constantinople in 1453 it spelled the end of the 1100-year Byzantine Empire. The Greeks had another far more potent weapon however, one that has stood the test of time. It is a weapon of such power that no one who comes under its influence can withstand its force. Designed by Plato and Socrates and then Aristotle it was perfected by the Hellenistic philosophers of Greece during the 3rd century BC.

Its name was Eudaimonia. Its power lies in that unlike Greek fire that works materially from without, eudaimonia works mentally from within. Unlike Greek fire, it benefits friend and foe alike as it is based on one’s own natural ability to think freely for oneself. Meaning literally having a good daemon within you, eudaimonia is the most effective mind-altering drug of all time. Unlike other material drugs, it is free and completely safe with no adverse side-effects. On the contrary, those who use it attest to its life-long benefits of happiness, tranquillity and a peaceful mind. It is a stress-buster designed to cure anxiety by enabling those who practice it to be happy or at least not unhappy no matter what ill fortune may befall them.

The secret weapon of eudaimonia is the enduring gift of Greek philosophy to the Western world. As the Roman Stoic philosopher Seneca observes in one of his letters to Lucilius ” Who can doubt, my dear Lucilius, that life is the gift of the immortal gods, but that living well is the gift of philosophy?”

In a current biography of the 16th century French thinker Montaigne, How To Live, the author Sarah Bakewell makes the important point that Montaigne’s guidance for how to live well came from the three central Schools of Hellenistic philosophy: those of the Stoics, the Epicureans and the Sceptics. Psychological and social studies today seem to confirm the philosophy of how to live well, first expounded by Plato, Aristotle and then the Hellenistic philosophers. One could say that those philosophers and in particular the Stoics, were the first psychiatrists of the ancient world. In his popular book, Plato, Not Prozac! Lou Marinnof makes the point that Greek philosophy can cure anxiety and unhappiness and probably some mild forms of depression.

Being of a sceptical disposition, I suspend judgment on the strength of that claim, though it could well be true, and there’s no harm in trying. So what does the Greek philosophy of Eudaimonia amount to? In a nutshell: For the Epicureans, the source of happiness is simple living through the pursuit of simple pleasures and the avoidance of those that are likely to cause us anxiety – the pursuit of excessive wealth, power and fame; for the Stoics, it is a good character based on virtue that guarantees our happiness (the cardinal virtues of courage; moderation; prudence or practical wisdom; and justice) and for the Skeptics, the source of happiness is the total suspension of judgement (epoche) as nothing in the universe is certain so why lose sleep over trying to know what cannot be known? One might as well stop worrying and start living by simply going with the flow.

However different the details of these three philosophical perspectives were, and there are important differences, they all held in common the central idea that happiness lies in freedom from anxiety – ataraxia – peace of mind or equanimity, both in the face of success and failure.

Moreover, all three schools of philosophy held that to be happy is within one’s control as one can be happy, or at least not unhappy, by simply not trying to control circumstances and conditions beyond one’s control. What’s important is to instead change our attitude towards those things that lie beyond our control. Interestingly, the meaning of eudaimonia, which places one’s capacity for being happy within one’s control, contrasts sharply with that of the modern Greek word for happiness, eutichia, which places one’s ability to be happy outside one’s control by making it hostage to fortune.

Its then pure lottery whether you turn out to be happy or unhappy. As the current volatility of the stock market has shown one would be unwise to place one’s happiness in the hands of fortune. Mush safer to keep it inside one’s mind, where it belongs, instead. The Hellenistic philosophers were all about attitude. Misfortune cannot make you unhappy if you choose not to allow it do so.

Death is part of the human condition whether we like it or not, so there is no point in making yourself unhappy by unduly worrying about it. In fact for Socrates, philosophy is a preparation for death. It allows us through reflection and practice to look upon this ultimate evil with total equanimity. And as we know, Socrates was a man of his word. He did not flinch in the face of death but remained peaceful and steadfast throughout his ordeal. In this age of constant change and chronic uncertainty the Greek philosophy of eudaimonia offers a sanctuary of consolation and tranquillity. Ataraxia is the new cool.

* Dr Edward Spence is a Senior Research Fellow at the Centre for Applied Philosophy and Public Ethics (CAPPE), Charles Sturt University (CSU). He teaches philosophy and ethics in the School of Communication and Creative Industries.