Aside from the fact we'd still be hitting each other with rocks because it made a nice wet thwacky noise, we would not have the Higgs-Boson, democracy, fountain pens, flu remedies and lots of other marvellous things which make life today more bearable than any number of yesterdays.
Of course not everyone learns, which is why we still have police tasering elderly blind men, laws which make it a crime to be sarcastic, and Tara Palmer-Tomkinson falling in and out of parties looking a right mess.
But, generally speaking, humanity improves itself - sometimes with a speed below that of continental drift, admittedly - by learning from its mistakes.
And it's just as well, because think about how appalled we would be if we ignored them. Picture what would happen if a journalist today was found to have hacked the voicemails of murdered schoolgirl Tia Sharp, or the BBC had recruited a career-long pervert as a children's TV presenter.
We'd not only be shocked at their stupidity, we'd be aghast at their amorality. Even more aghast than we were the first time such mistakes were made, because it is only the hope that mistakes are learned from which make them bearable in the first place.
Which brings me, with angry inevitability, to the MPs' expenses scandal of 2009.
This is a story which so rocked the nation's already-shaky faith in politicians that, in all likelihood, it was partly responsible for the fact no party won a majority in the 2010 General Election and we got a Coalition they tacked together themselves without asking us about it.
It was so major an event that it altered our likely government, and thus the policies it enacts for the following five years. It was not a flash in the pan, not a Silly Season media frenzy. It was a biggie.
Vast numbers of our elected representatives were stealing millions of pounds from the public to line their own pockets in what can only be described as a system of institutionalised fraud. They wrote their own very relaxed rules about claiming for anything up to £250 without receipts, switching their second home allocations and buying furniture and kitchens from expensive department stores, and when they found even those rules too restrictive they broke them.
Some claimed for things that were not allowed, like cutting their wisteria, £380 for horse manure, mortgage payments for houses while they rented another out for profit, a £1,645 house for ducks, repairs to their tennis courts, claiming £400 a month for food, and avoiding capital gains tax.
Still more produced fake documents to claim for mortgages and rent that did not exist. It claimed the scalps, over time, of six Cabinet ministers, 13 backbenchers and five members of the House of Lords who either resigned, stood down, retired early, were suspended or jailed.
They whinged and whined, but many had to pay back thousands in false claims and missed tax. It led to an upsurge in the number of independent candidates at the next election, and the most senior and important job it cost was that of pugnacious Speaker Michael Martin.
Martin had tried to block publication of the expenses long before the scandal broke. When journalists and a handful of MPs were campaigning for transparency and using the deeply-flawed Freedom of Information Act to force the issue, Martin insisted on as little transparency as possible.
He employed ex-SAS staff to handle the 'sensitive' material; he claimed to be protecting the 'security' of MPs whose home addresses should not be included (which would later prove their second home flipping, dodgy rental agreements and other lies); he oversaw debates in which MPs rejected calls for reform; he fought and delayed and when he could not stop publication he demanded massive redactions throughout.
Unfortunately for Mr Martin, and luckily for the rest of us, one of those ex-SAS staff was horrified at what he saw in the raw data and hawked it around the newspapers. Journalists were shown small details to see if it was worth their buying all of it, and snippets appeared here and there. The problem was there was so much information, and so many stories, that no mass-market paper could ever use all of it and no deal was struck.
One saw a way to do it justice, and the Daily Wellygraph paid £110,000 for the full set of info. They locked some journalists in a room for weeks to crunch the data day and night, and then they went big on the story every day for weeks.
Martin's response was to call in the police and criticise the media. He sought to punish the whistleblower, shoot the messengers, harangue MPs who denounced the scandal to the Press, and otherwise sought to cover everything up with the fat old man's favoured weapon of a giant harrumph.
It ended badly, of course. The MPs he was supposed to control turned on him, and those keen to find a scapegoat for their own failings denounced him, voted him out of his job and waved him off to bitter retirement while saying this could all never be allowed to happen again.
Yesterday his replacement as Speaker, John Bercow, was asked to 'protect' the 'security' of MPs and not allow their addresses to be revealed in a FOI request aimed at finding out where, exactly, they were claiming taxpayer's money for living.
The request centres on who the landlords are of those MPs who are claiming rent because, as we know all too well, they have a habit of renting from each other, secret boyfriends, and their own family.
Mr Bercow has asked the authorities to "reconsider" publication of the landlords' details as it "could involve causing unwarranted damage and distress" to the shrinking violets of the Commons if we knew where they lived and who they were renting their houses from.
Never mind that their home addresses - or at least, the addresses of one of their homes - are matters of public record. You can't stand for election unless you're on the electoral roll, so if someone is determined to damage and distress an MP it's a matter of some ease to bang on their front door and annoy them. That's how I do it, after all.
If they're not at home they're normally in the big palace we pay for, drinking booze we pay for or eating food we pay for, and if you can't get into one of the public areas you can always hang around outside and distress them on their way back to a London flat we also pay for. They haven't made that a crime, yet.
Bercow acted despite the fact that the Independent Parliamentary Standards Authority, which was set up in the wake of the 2009 scandal, has already admitted that four MPs are claiming expenses for renting from other MPs which, as far as I can tell, makes eight MPs on the make at our expense.
They might be the only ones, but I'll bet you the last shot of vodka in the bottle they're not.
There are many ways in which politicians can be differentiated, not least the good from the bad, the ones with a vocation from those best kept off the streets. But the one over-riding quality they always seem to share, regardless of their IQ, is a pig-headed, breathtakingly stupid degree of self-belief so misplaced it would make an X Factor contestant blush.
YOU DID THIS BEFORE. IT WAS BAD. DO NOT DO IT AGAIN.
What bit of that is so difficult to understand? What part of the expenses scandal made them look good? What exactly is possessing them to not only repeat the mistakes of the past but to find whole new ways of diddling the taxpayer and hope we don't find out?
There's not a journalist in the country with any wit who would hack a phone today even if they knew it would get Jimmy Savile bang to rights. Maybe in a year or two there would be a way for a reporter to write "we hacked a phone to get this story, and here's why you won't mind" in their copy and not get nicked, but no-one who's witnessed the public disgust and industry-wide witch hunt we've had in the past few years would have the death wish you'd need to invite it a second time.
Anyone who's got the tiniest skeleton in their closet and working at the BBC is currently spending their days gnawing their fingernails and praying the Savile sandal doesn't flush the whole corporation down the pan. There are officers at the Met who are very, very careful about not appearing racist, pathologists are keen to get organ retention forms signed in triplicate before they open the formaldehyde, and plenty of ordinary people up and down the country who, having screwed up once, do their darnedest not to do it again.
Everyone tries to learn their lessons so they're better tomorrow than they were today. Children of four years old manage that and even Tara Palmer-Tomkinson is trying, bless her. But not our elected representatives.
No, they still think the judges don't matter so long as they win the public vote.
The problem is they've forgotten the judges are us.
It's a no from me.