My mother grew up in a country in which more men toiled in factories, fewer women worked in the labour market, most couples were married, homosexuality was illegal, nearly everyone was white, television scarcely existed, the national anthem was played in cinemas, one of the world's two biggest powers was committed to communist ideology - and nearly three million people were members of the Conservative or Labour parties.
My son is growing up in one in which the old steel yards or coal fields no longer exist, most women work (at least part-time), married couples are now a minority of households, one in five people will be ethnic minority members by 2050, people communicate at the touch of a button through social media, communism has collapsed outside North Korea and Cuba - and under 400,000 people are members of the two main parties.
In other words, the way we live now is rendering political parties out of date. This isn't because people are less interested in politics than before. On the contrary, they are as caught up than ever - as the huge turnouts for the anti-Iraq war and pro-countryside marches during the New Labour years showed. In individualist modern Britain, they are far more likely to join single-issue campaigns than political parties that represent antiquated class interests.
In the 1950s, when my mother was a young woman, the Conservatives were the party of capital and Labour the party of, well, labour (though a third of the manual working class voted Tory, and Labour had more than its share of middle-class intellectuals). The fall of the Soviet Union gave Tony Blair the chance to blur those old class distinctions: under his leadership, Labour appeased the City and abandoned the workers - opening Britain up to new waves of immigration.
With big business at ease with the new corporatism and the politically correct codes that govern it, the old alliances which once made the Conservatives the natural party of government broke down. We haven't won an election for over 20 years. At a Parliamentary level, we scarcely exist in Scotland. Our condition is little better in the urban North and Midlands, in which we hold only 20 out of 124 urban seats. Vote distribution makes winning a majority almost impossible.
David Cameron steered us back to office on an impressive swing, but he didn't win a majority and the outcome of the last election was as much a protest against Labour as an endorsement of our Party. Early on in the leadership campaign that he won, Cameron let it be known that he considered himself "the heir to Blair". A key to the latter's style of leadership was using his own Party as a whipping-boy to win credibility with those who didn't support it.
Cameron's present charm offensive towards Tory MPs, of which the backing of James Wharton's EU referendum bill is a part, is a result of him having tested this Blairite mode of leadership to destruction. The tactics which worked so well for Blair in 1997 have worked less well for the Conservative leadership some 15 years later. Under Cameron, the Party has allowed a gap to open up on its right which Nigel Farage's party is trying to fill.
UKIP is essentially a single issue party of protest against the entire governing class, but Farage is presenting it to disillusioned Conservatives as "the Tories you used to vote for" - with his support for grammar schools and opposition to same sex marriage. It is bucking the falling membership trend, and probably has about 30,000 members: the gap between this figure and the Conservative Party's 130,000 or so is large but not unbridgeable.
What could fill it isn't so much the growth of UKIP, which has a natural ceiling and is vulnerable to the party's intrinsic weaknesses under first past the post, as the further fall in Tory membership as death and declining renewals take their toll. The disappointing by-election result in Eastleigh, in which MPs were parachuted into a seat with a defunct local Association, was a warning of things to come: parties that have no presence on the ground won't win or hold seats.
In short, what George Osborne once called uber-modernisation, with its doctrine of taking on one's own supporters, is exhausted. What's left is frighteningly close to being an empty shell. I am a member of the Party. On paper, this should mean that I have some say in its profile and policies. In practice, it means that I pay a minimum of £25, and in return receive letters from Cameron asking for more money.
I have no formal say in policy-making. Conference attendance is expensive: indeed, conference is now a trade fair for lobby groups rather than an occasion for Party members. I may have little say in the selection of my local Conservative Parliamentary candidate. The rules for choosing candidates for the European Parliament are bewilderingly variable. Senior MPs are discouraged from speaking at events organised by Associations in seats we hold.
This is rather like Tesco refusing to send senior managers to stores based in profitable areas. In short, this model is no longer sustainable. It is probably impossible to reverse the slide in membership, but it must be possible to raise the rate of participation. The news is not all bad. Some local Associations have bucked the trend in falling numbers. Grant Shapps's Team 2015 initiative points the way to a possible future outside the present Association structure.
If David Cameron is Prime Minister after 2015, there is likely to be a referendum on Britain's EU membership two years later. Over the same period, we need to ask ourselves some hard questions about the Party's future. Should membership be for a minimal cost - or even free? Should the present Association structure be ended or adapted? Should the Party build on Shapps's initiative, and recruit nationally from the 800,000 people online who identify as conservatives?
Should such supporters, rather than members, select candidates? Is the Party's structural future one of organising overlapping campaign groups, rather than operating as a single central entity? Should Party Conference have a formal role in policy-making, and should CCHQ be more independent of the leadership, allowing for better long-term campaign planning? Indeed, should the Chairman, be an elected post? If not, should some of his or her deputies?
I don't know the answer to these questions yet, but am certain that they are in the right territory. The Conservative Party is the oldest, and arguably the most successful, political party in the world. It has survived because of its ability to adapt - reinventing itself time and again when the chances of its flourishing seemed long. Mass membership may be dead. But there's no intrinsic reason why the Party shouldn't be alive and well in the era of my grandchildren.
Paul Goodman is executive editor of ConservativeHome. He was the Conservative MP for Wycombe between 2001 and 2010.