Reading the reports from the inquest into the Edgware tube bombing and the advance publicity for Jeremy Paxman's interview with Christopher Hitchens for Newsnight, I wondered if there was a useful distinction to be made between bravery and courage.

Like anyone following the 7/7 inquest, I find it incredible that a random selection of people who happened to be either on the train that left Edgware just before 8.50am, or in the adjacent train, threw up so many individuals who did not simply act with great selflessness but insisted through the hearing that the words "hero" and "bravery" when applied to them were completely inappropriate. Wing Commander Craig Staniforth, Methodist policy adviser Steve Hucklesby, former Austrian soldier Adrian Heili, Jason Rennie, a South African, and British teacher Timothy Coulson were among those who said that, beyond giving evidence to the court, they did not want to make anything out of actions that came naturally to them in that tunnel.

In any arbitrarily chosen group, it seems that the proportions of modesty and heroism are likely to be quite high, for the bombing of the Aldgate tube train produced equally impressive accounts of ordinary people thinking quickly and stilling their own fears to help others. A psychologist quoted last week suggested that those with crisis training cope better with the levels of stress, yet there are as many stories of people who had no training responding with extraordinary presence of mind after the 7/7 attacks.

Saying that this kind of heroism is more common than we realised does not diminish individual acts of bravery in any way; rather, it seems to underline the small recognition given to the miracle of spontaneous human selflessness. This is something that plainly lies in many of us and, like shyness or generosity, cannot be predicted by experience, class, intelligence, race or physical strength.

The premeditated act of heroism perhaps requires a little more from a person because the imagination has time to do its worst, to figure out the likelihood and, indeed, nature of the death, injury and pain that may be result from a particular action. Consider the thoughts of Staff Sergeant Olaf Schmid as he made the long walk to disable 64 roadside bombs before being killed in Afghanistan a year ago, or the dauntless Lieutenant Colonel Angus Macgillivray of the Black Watch who, without sleep for 30 hours, led his men through unforgiving country to capture Taliban insurgents, a pile of intelligence and numerous roadside bombs. For their gallantry, Schmid received the George Cross and Macgillivray the Military Cross.

Last week, a VC, awarded posthumously to the footballer Donald Bell in 1916, was bought for £252,000 by the Professional Footballers' Association. There seems something a little off about the purchase – not the selling of these awards – but you see why the PFA wanted the medal when you look up the records. With his battalion pinned down by machine gun fire, Bell crept up a communications trench, then with incredible turn of speed he dashed across open ground, shot the gunner and killed up to 50 men with hand grenades and bombs. He was later killed in a similar exploit.

Gallantry, with its slightly suspect ring of chivalry, is an interesting word to use for what is effectively slaughter, but few of us can imagine what it is like to see friends mown down by machine gun fire. The records contain a tribute from a fellow officer of Bell, in which he said: "He always seemed to be on the lookout for ways and means of making things easier for his comrades. He was ready to risk his life many times over if only he could lessen the risk to his men and brother officers." Bell was doing it for his mates, and lest anyone makes the error of suggesting that Mohammad Sidique Khan's actions at Edgware Road required no less heroism than Bell's, it should be obvious that Khan was killing and maiming defenceless people, while Bell was attacking armed combatants. One was murderous suicide, the other valiant sacrifice.

The more I think of it, the more time separates the three classes of heroism – bravery, valour and courage. The last two certainly occur when there has been time to consider all the options, including flight or cowering in a foxhole, and then a person risks everything to go the aid of his fellow men and women. But the differentiating point about courage is that it is usually sustained over a long period of time and requires endurance.

Mark Twain has been over this ground but gets it slightly wrong. He said: "It is curious that physical courage should be so common in the world and moral courage so rare." In effect, why, if there are so many starlings, there are not more nightingales. Physical and moral courage are different species and while sometimes found in the same person they have different origins.

My chum Christopher Hitchens is an interesting case. He has always cheerfully put himself in the way of physical danger – posing by unexploded bombs in the Middle East and nearly being lynched while lecturing a mob of fundamentalists in Lebanon – but Christopher's mettle is now seen with his reaction to terminal cancer. He has led his life bravely, causing no end of offence to opponents, as well as dismay to those who made the mistake of assuming he was an ally and whom he then drubbed with fratricidal glee. I cannot think of anyone who has stirred things up quite as much as Christopher, nor in the process provided so much amusement with his writing, but the important thing is that his fearlessness stimulated people to think for themselves.

That was all kid's stuff compared to his current struggle. In his interview with Paxman, he faces it squarely and with a remarkable lack of self-pity or sentimentality, an important component of courage. He has had to put up with a lot in the last five months, about which he seems stoical, but it must have been hard to take the responsibility for his family's pain. "For my family, it is not very nice," he says. "I could wish perhaps to have led a more healthy and upright life for their sake."

Despite Mark Twain's observation, moral and physical courage are often on show, particularly in the final accounts of a life where they come to represent the refined products of character and experience. We are constantly surprised how common all forms of heroism are, perhaps because we are used to dismissing this part of ourselves, a habit inculcated at school and nourished by the institutions of government. But the thing I increasingly take from the news and watching people I know go through various crises is that we are better than we know.