Among the films currently showing at Cineworld Edinburgh, you can take your pick from Dark Shadows, What To Expect When You're Expecting, and Moonrise Kingdom.

You couldn't drag me to any of them, even if you happen to have a couple of wild horses handy. But there wasn't much more entertainment on offer at Friday's showing of The Dictator. Hang on, I've got that wrong. It's showing now. Alex Salmond was the feature presentation on Friday.

The First Minister was kicking off the Yes Scotland campaign, a cross-party grouping of SNP members and residents of New York, in the person of the actors Brian Cox and Alan Cummings – though the latter, whom older readers may remember as the quintessential Kelvinside man, Victor, or possibly Barry, announced he was moving back to Scotland especially to cast his vote.

There was also Patrick Harvie of the Greens, the only man in the room trying to forget about North Sea oil and the money it brings in. And a filmed message by Shir Sean from Shpain. And, er, that's about it.

Media commentators were underwhelmed by this vision of Sunrise Kingdom (we're not, despite the song, making our land Republican in the Scottish breakaway, having worked out that quite a lot of voters like the Queen). All right, it wasn't Avengers Assemble – $1 billion at the box office and still going strong – but I think they're being a bit unfair.

I don't know what they were expecting to inspect, but I have some sympathy with the response of Blair Jenkins, BBC Scotland's former head of news, when asked whether people were being asked to sign up without the facts. "Well, yeah," he said. "It's about hearts and minds in a broad sense, rather than the detail."

This is a perfectly sensible position – certainly more sensible than the insistence by some Nationalists, notably those with an internet connection, that everything will automatically be better and that the sea will turn to lemonade.

The truth about what may happen after independence is that nobody knows the facts, and they won't unless and until it happens. It has this in common with all other hypothetical things which may or may not happen in the future. The ubiquitous Professor John Curtice of Strathclyde University suggests that voters may opt for independence if they can be persuaded that they will be £500 a year better off. Perhaps. Though if Scots voters are that keen on prosperity, there remains the puzzle of why they keep voting for left-of- centre parties.

The policies of the SNP, and the readiness of its leadership to trot out fanciful assertions about how rich Scotland would be, are the main things that make me sceptical that independence will put more money in our pockets. The most reliable GVA figures seem to suggest an independent Scotland would be slightly worse off than the remainder of the UK, but slightly better off than the remainder of the UK if you don't include London.

But, whatever Prof Curtice thinks, I hope he's wrong. If the overwhelming motivation for choosing to separate from the rest of the UK is that you'd be £500 to the good, it's a pretty terrible reason to vote yes. It's worth looking at the figures critically, and asking about such things as fiscal control, but it would be silly to base support for or, more likely, opposition to independence on the question of whether Scots would be slightly better or worse off. It simply isn't credible to maintain that the country couldn't function economically if independent, and whether it prospers or flounders thereafter would depend on the policies of the government Scots then choose to elect.

Similarly, the SNP may have inadequate answers to questions about disentangling the welfare system, pensions rights, the armed forces and so on, and about the prospects for Nato membership, defence construction and other issues, but that is not wholly surprising. Hammering all that out may be much more complicated than they admit, but it is not beyond the wit of man. And, as at least a nominally broad church, there's no reason why the Yes campaign should all agree on the answers. Though it would be nice if, before signing up to it, people bothered to ask themselves the questions.

Voters will consider economic and social factors, of course. And if they then decide to stay in the UK, it would be as dishonest of independence's advocates to claim that this is mere timidity, or that they are incapable of weighing up the advantages and disadvantages, as it is for Unionists to argue that independence is impossible.

But though I find those arguments in favour of the Union convincing, Mr Jenkins's point is actually the one that matters. It will be sentiment which decides most people. Sentiment, I hope, rather than sentimentality. The latter is indulging one's feelings, but the former is a mode of thought influenced and informed by emotion.

At the moment, I think that the no voters will prevail because, at root, Scots are reluctant to make foreigners of their family and friends south of the Border. That is the main obstacle for the Yes campaign to overcome and, I suspect, the one which will really matter in the end.

But it is still a huge obstacle. That is why Mr Salmond needs to put off the referendum (there is no other possible justification). But it's also why the Yes campaign's objective – one million signatures in favour of independence – is not, as some commentators claimed, an admission of defeat, since that's not enough votes to win. It is a recognition that if people want to vote yes, they will have to be convinced and committed.

They aren't yet. Despite the SNP's electoral success at Holyrood, William Hill's odds on Scotland being independent by 2020 are currently 16-1 on for no, and 7-1 for yes. But the odds follow the money, and they can change over time.

If enough people can be convinced to sign a pledge, that may influence others.

After all, when you see hundreds of people queuing round the block for a film, you may start wondering if you ought to see it yourself.