A greener, fairer and more prosperous society: what's not to like?

The Yes Scotland campaign for independence was duly launched yesterday with the expected razzmatazz and star names designed to create a positive, confident atmosphere.

The SNP have already proved the worth of an aspirational message in gathering votes. But with the poll commissioned by the No campaign reaffirming, on the day of the launch, that only one-third of Scots are currently prepared to vote in favour of independence, the need for more substantial argument cannot be ducked.

With yesterday's launch, the Yes campaign cleared its first hurdle in style. This was to demonstrate that its support is not confined to the SNP and other parties which are committed to independence. While Patrick Harvie, co-leader of the Scottish Green Party, lining up alongside Alex Salmond was to be expected, it will be the activists from other parties and non-political supporters that will prove crucial in attracting back-up from the one-third of Scots voters who are not committed either to independence or to Scotland remaining in the UK.

Celebrity endorsements from Sir Sean Connery and Alan Cumming provided the mandatory glamour, with Tommy Brennan, the shop steward who fought to save Ravenscraig, declaring he had no fears about independence, and Liz Lochead, Scotland's Makar, proudly disclaiming any political allegiance, illustrating the breadth of support. But it was the personal testimonies, which at times brought the atmosphere closer to confession, that underpinned the event with credibility. Dennis Canavan, a Labour MP for 25 years and an independent MSP for eight, explaining that he backed independence because it would be a step towards social justice, took the campaign beyond party political interest, a stance boosted by his well-known disagreement with the SNP over the retention of the monarchy.

In declaring that he was proud to be the voice of New Labour in 2007 and still espoused Labour values, Brian Cox, the Dundee-born actor, conveyed to Labour voters attracted by independence the idea that they would not be alone in concluding that Scotland would be better off controlling its own destiny instead of leaving it to the Westminster Parliament "which has not the foggiest clue about Scotland's cultural, economic and social needs".

Launching a Declaration for Independence created a link with the symbolic Declaration of Arbroath but the goal of attracting one million signatories by the date of the referendum will also provide a much-needed focus during a lengthy campaign that will test the stamina of those on both sides. Celebrity support cannot take the place of thoroughly fleshed-out arguments. It has taken the year since the SNP's election victory for questions such as whether an independent Scotland retains the pound as currency, fiscal union with the rest of the UK and membership of Nato to become widely discussed. The Yes campaign should now recognise that the hearts of Scots are in the right place and that the outcome of the referendum will depend on which side makes the more convincing case.