Fine Gael's line is that we already have a forum on Europe, and it's called the Oireachtas. On the eve of the first gathering of politicians and interest groups in Dublin Castle for the forum this week, Mr Noonan gave his reasons for staying out.
With the Government divided on Europe and its policy in disarray since the defeat of the Nice Treaty referendum, he wasn't going to be sucked into some false consensus-building project to help them out.
"The Taoiseach loves consensus," said Mr Noonan. "He'd wrap his arms around us and say we are all in this together. But we're not: we are not in Government. We are the Opposition," he said.
While the forum was going on, "the Government will be making decisions about Europe every month, which can't be challenged because everybody is tied into this consensus.
"This type of false consensus is a disaster. It suits the Taoiseach, it suits the Government but it doesn't suit the people and it doesn't suit democracy."
He made clear that he planned to exploit Cabinet differences on Europe rather than allow them be subsumed into the forum. The differences over Europe masked a more fundamental division in the Coalition over social policy, he said.
The Boston versus Berlin debate was code for whether we wanted a Washington model of lower taxes and lower social protection or a Brussels model of higher taxation, social protection and services. He said he was a Brussels man.
Others in his party pointed privately to the general consensus on Northern Ireland, and on the principle of social partnership.
At Dublin Castle on Thursday, however, it is clear there will be no all-embracing consensus. Indeed, Mr Noonan's party is part of an overwhelming Dβil consensus behind the Nice Treaty - a consensus not shared by the people in last June's referendum - but that is not necessarily the way the forum is going to go.
After the Taoiseach's opening speech on Thursday afternoon came Mr Ruair∅ Quinn, Mr Trevor Sargent and Mr Joe Higgins, all of whom laid into the Government from various positions.
Also watching in St Patrick's Hall were Mr Seamus Healy TD, Mr Mitchel McLaughlin of Sinn FΘin and representatives of the Peace and Neutrality Alliance, the campaigning group AFrI and others who successfully opposed the Nice Treaty.
These will all have important roles in the coming debates, and say they will use the opportunity presented by the forum to highlight their concerns over neutrality, loss of national sovereignty and other issues that concern them.
The chances of the forum producing a single agreed report are slim. When its proceedings are complete it is likely to publish them, together with a summary and various appendices. However, if the forum even tries to agree a series of conclusions these are likely to come in the form of majority and minority reports, with lots of dissenting opinion at every turn.
With an overwhelming Dβil majority in favour of the Nice Treaty, the forum is likely to take steps to ensure that those who question the direction of the European project receive a substantial role.
While the membership of the forum is confined to TDs and Senators, the special "observer pillar", consisting of campaigning groups on both sides, will be allowed an active status.
As witnesses, experts and campaigners give their evidence, the observers will be allowed to ask questions and make contributions. They will be given all documentation in advance along with forum members.
Next Thursday, the first formal session will hear from three international academics or policy analysts who specialise in European affairs, at least one of these coming from the ranks of Euro-doubters.
Each speaker's presentation will be followed by a question and answer session, and the day will end with an open discussion. The formality of past forums - such as the Forum for Peace and Reconciliation where speaking time was allocated strictly in accordance with party size - will be kept to a minimum with fluid, inclusive debate being encouraged between members of the forum and the observer pillar.
The second session is likely to hear the views of the applicant member states. The three or four speakers from such states will include representatives of the anti-EU groups in countries where such sentiment is strong, such as Poland or Malta.
The third session will be one in which the observer pillar itself will take centre stage. Pro-neutrality groups and others opposed to Nice will outline their positions together with pro-European organisations such as the European Movement and the Institute for European Affairs.
There will then be several sessions on specific themes, and the forum is likely to travel outside Dublin for at least some of these.
A session on the effects of enlargement on agriculture, for example, may take place in Cork. Other themes to be examined include the environment, security and defence.
When the first phase of the forum's work is complete - within about three months - there will be a review meeting at which the first attempts will be made to draft a report and conclusions.
It is hoped that the fact that the forum is taking place will raise public consciousness as to the issues, and will attract media coverage. But the prospect of consensus, at this stage, appears remote.