The actor Simon Russell Beale was recalling recently how, while studying English at Cambridge, he had had such a brilliant idea about Macbeth that he needed to go and calm down for several hours in the College Buttery. He can't remember what the idea was.
It's a bit like those drunken nights when, raddled with emotion, you arrive at a phrase that seems to address the whole sad, beautiful business of life, and you write it down, and the next morning you read "Connection the key - but no false bridge" or "Leaf equally important as sky".
Which is to say, not all inspiration is significant - or even inspiring.
The word "inspirational" is loosely used in connection with sporting achievements. But some performances emerge which merit the description, and Roger Bannister's sits comfortably in that category.
With the 50th anniversary of Bannister's first sub-four-minute mile looming - it falls on May 6 - our television screens will soon feature the familiar footage from that chilly evening at Iffley Road. The long-striding medical student, freed from his fading help-mates Chris Chataway and Chris Brasher, strains towards the tape, disappearing behind the figures gathered at the finish line before collapsing on to the shoulder of his tweed-capped coach, Franz Stampfl, blond hair flopping over his exhausted face...
The records tell their own story of the significance of that race. Having become the first man to run the mile in three-minutes-something since records began in 1875, Bannister repeated the exercise three months later in defeating Australia's John Landy at the Empire Games.
But Landy, who also ran inside four minutes, had already responded to Bannister's breakthrough within the space of six weeks by lowering the record from 3min 59.4sec to 3:57.9.
The following year, three others entered the fabled sub-four territory, including Chataway; the year after that, five more followed.
"Après moi, le déluge," Bannister commented in the wake of his supreme effort. He wasn't wrong. What resonated, beyond the record itself, was his conviction that it could be achieved.
This week, in the unlikely environs of London's Brick Lane, a modern-day successor to the man who went on to become a brain surgeon and the Master of Pembroke College, Oxford was flexing her muscles for the benefit of the cameras.
During the last two years, Carolina Kluft has accrued European and world titles in the heptathlon. But what marks the 21-year-old out as an especially influential athlete is her attitude.
"Going out and having fun" while competing is something of a mantra in athletics circles, up there with "taking each race as it comes", or "staying focused".
Where Kluft differs from the average runner and jumper is that she truly believes in having fun, and so transparently does, even at the most demanding of moments. The Swede's ability to communicate emotion to a crowd is innate, as unmistakeable as on-screen presence.
In the bewildering confusion of activity that takes place during any major championship, it is always easy to pick Kluft out. The odds are that you will hear her before you see her as she prefaces each endeavour with a wild slapping of thighs and a sequence of urgent imprecations.
This attitude is special, and without price for a sport currently striving to maintain its appeal amid a welter of doping cases.
Kluft's visit to the capital five months ahead of the Athens Olympics saw her being smeared with purple, liquid rubber in order to form a cast that will enable her statue to be created in the classical Greek style.
It was not something with which you could ever imagine Sir Roger becoming involved, but then so many things have changed in sport within the last half-century.
What endures, within certain individuals, is greatness of spirit. And you can't make a cast of that.Reuse content