Modernity is, in some ways, a curious concept. All generations naturally think of themselves as modern. They look back with amusement and some condescension at the overly constrained, sepia-tinged visions of their grandparents -- before they, too, become objects of amusement for their grandchildren.

But in a broader historical perspective, these cycles of subjectivity give way to a clearer structure of well-defined progress. From the philosophers of ancient Greece to the engineering marvels of the Roman empire, through the Dark Ages to the Renaissance, the Enlightenment and into the atomic age, there is an incontrovertible backdrop to humanity's achievements and a clear set of cultural, community and intellectual values relevant to each age.

Perhaps no human being is more representative of the transition from one age to another than Galileo Galilei, the Italian pioneer whose life straddled the 16th and 17th centuries. Galileo was undoubtedly one of the most influential scientists in human history: a prodigious intellect who overturned Aristotle's 2,000-year-old laws of motion, an inventor of numerous mechanical devices and a passionate advocate of the controversial Copernican view of the solar system who discovered remarkable experimental evidence (the moons of Jupiter, the phases of Venus) to support these theories

Yet despite these numerous, transformative scientific achievements, Galileo's long-standing fame and iconic status likely owes less to the discoveries themselves and more to the way he promoted his unsettling views and the consequent struggles with the authority of the Catholic Church.

A notoriously proud, arrogant and provocative individual with a formidable intellect and no great tolerance for fools, Galileo had a complicated relationship with the church throughout his entire life, from his youthful determination to join a monastic order to his eventual trial (and subsequent public abjuration of his beliefs) by the Inquisition.

Scientists today worship Galileo more as a sort of scientific freedom-fighter, a revolutionary who proudly and vocally placed his faith in the scientific method rather than bow to arbitrary constraints imposed by authority figures determined to suppress discoveries not in keeping with their world view.

In staunchly defending his theories of the universe, Galileo was emphasizing much more than his research views per se. He was the first public advocate of the notion that science must be practised in plain view, untethered and untarnished by how we might feel the world should be.

It was this very concern that science should be a public activity that strongly motivated playwright Bertold Brecht to write his celebrated play The Trial of Galileo. Written at the beginning of the Second World War when the globe was reeling from the horrific effects of a more pernicious untrammelled authority, Brecht astutely recognized one of the great ironies of Galileo's achievement: by severing the link between science and religion and allowing scientific thinking to flower solely according to the dictates of reason and mathematics, he inevitably diminished the impact of science to the common man, even while he ensured the conditions best suited to making such discoveries.

"As far as these particular sciences are concerned," said Brecht, "they never again regained their high position in society, neither did they ever again come in to such close contact with the people." In this way, Brecht calls Galileo's "crime" of publicly challenging the authority of the Catholic Church in matters scientific "the 'original sin' of modern natural sciences."

For those of us who spend untold hours trying to engage the public in discussions about the wonders and mysteries of science, the force of Galileo's "original sin" can still very much be felt.