In the 19th century, it was charities that changed society, charities responding to the new urban problems of industrialisation.
Ms Young says social entrepreneurs get things done
In the 21st century it may be time for something new: social entrepreneurship, for example.
It means taking a business eye to the problems of society, and then applying a business imperative to get things done, but without the profit motive.
I think this is terribly important, and so (luckily) do people with the money to invest in it (unlike me, that is).
Social entrepreneurship is getting a lot of attention.
Even business schools are waking up to it as a subject that needs to be taught.
At the Said Business School in Oxford the other day, Rowena Young told me how they are teaching it there, and how keen people both inside and outside the university are to learn about it.
She is director of the school's Skoll Centre for Social Entrepreneurship.
A changing society gives social entrepreneurs new objectives she says: they may come up with unconventional ways of addressing the problems of a rapidly ageing population, for example.
This is different from the charity approach, says Rowena Young.
They say how do we grow?
Social entrepreneurs ask how to resolve the issue, and move on to the next one, just like business entrepreneurs.
The Said school is only 10 years old, but it is already producing its own ex student social entrepreneurs, such as Clean Start Energy making bio-diesel fuel in India with founders only one year out of college.
Professor Yunus spearheaded unsecured lending to the poor
The fuel comes from a weed which was taking over the land of poor farmers.
If you want to, half your Oxford MBA can come from studying social and environmental innovation.
Business students, says Ms Young, want increasingly to marry their values to their professional careers without having to make a choice between the two.
She says it is a growing trend for people under 35; big businesses will ignore it at their peril.
The Said School is also where the Skoll Foundation (based in Silicon Valley USA) has funded this department to study social entrepreneurship, and where it holds an annual conference, bringing commentators and entrepreneurs together from all over the world.
Ms Hale wants to use Big Pharma's existing discoveries
The Skoll in question is Jeff Skoll, a still young businessman who made a fortune as president of Ebay, but who now devotes himself to backing films and encouraging social entrepreneurs in a hurry to change the world.
One of the social entrepreneurs I met in Oxford as Professor Muhammad Yunis, founder of the now famous Grameen Bank in Bangladesh.
He is one of a huddle of new microlenders who are changing the lives of poor people by lending small sums of money to them, without the conventional security to lend on: collateral such as property, which is what most banks require to offset a loan.
The second social entrepreneur I listened to in Oxford was Victoria Hale.
She is the founder of the Institute for Oneworld Health, a pharmaceutical company based in San Francisco set up not to make profits but to do good, perhaps huge good.
She is doing something that the people who run "Big Pharma", the world's leading drug companies, cannot imagine ever succeeding.
Ms Hale is trying to create new medicines to treat illnesses common among poor people in places such as Africa.
And where does a not-for-profit pharmaceutical company find its new drugs ? Simple, she says on the shelves of Big Pharma.
Her message to the big companies is: let us have your drugs that for some reason failed to dazzle the first time around, drugs stuck in the company vaults.
And they do: the big companies are the ones who are making the Institute possible.
They have discovered and identified hundreds if not thousands of new compounds which have failed: not effective at the task they were produced for, unsuitable side effects, too small a market place for the huge costs the international giants have seen become a norm in their particular big lab, blockbuster drug model of the business.
Ms Hale, social entrepreneur and pharmacologist, says there is another model of how to develop drugs.
Oneworld Health can only do its job because Big Pharma is still profligate in the way it produces potential drugs.
But it also suggests that there are huge inefficiencies in the way western world drugs are currently devised and produced.
Challenging the system does not come cheap: among the backers of Oneworld Health is the Bill and Melinda Gates Foundation, which has given Victoria Hale $140m to change the way drugs are produced for the poor.
But we need dozens, no hundreds, more social entrepreneurs to change the way everything is done: to spot a gap in the social marketplace and fill it, with a motive other than profit.
They are on their way.
Work in Progress is the title of this exploration of the big trends reshaping the world of work as we steam further into the 21st century; and it is a work in progress, influenced and defined by my encounters as I report on trends in business and organisations all over the world.