School chaplains have no chance of winning over pupils if they are given just five minutes at 8.30am to deal with the great moral matters of the day.
They have even less chance if they are following the headteacher who has been berating pupils for various misdemeanours.
Ewan Aitken, the local authorities' education spokesman and former chaplain in Leith, called for weekly or fortnightly sessions in primaries and monthly or termly events in secondaries where pupils could be given time for spiritual reflection.
Mr Aitken told Church of Scotland representatives on council education committees at their conference in the capital that they could no longer speak to one particular faith group. Religious observance had to have a broader base. Seven per cent of primary pupils in Edinburgh come from ethnic minority groups and many others are aligned to no faith community.
There were strong arguments for avoiding whole-school events because of differences in age, apart from the logistics of bringing everyone together for an assembly. But the whole school should have the chance to reflect in year or class groups.
"The event must not simply be an intellectual exercise but one that draws on the experiences, wisdom and liturgy of a wide range of faith communities. The use of music, light, drama, images, computer graphics, silence, candles and other similar resources should be encouraged, as well as the spoken word," Mr Aitken said.
Events should include challenges and affirmation from daily life and the achievements and stories of the school community. These should be followed by time for discussion in small groups, to dovetail with the citizenship aspect of the national priorities.
At present, religious activity in non-denominational schools falls into four categories: responses to a crisis, such as the death of a teacher or pupil; recognition of religious calendar events; collective rituals such as chaplains saying prayers at prize-giving; and assemblies led by school staff or outside speakers.
Mr Aitken, a former minister in Edinburgh and now the city's education spokesman, advocates dedicated spaces for observance, such as the contemplation areas in schools built under a public private partnership (PPP). Catholic schools already have oratories.
He accepted his views would be challenged within the church and among his political colleagues but argued that "education must be the cradling of the soul, as much as a feeding of the mind". Young people had to be given space to work out what they believe in, even if it is nothing, and what the consequences would be for their lives.
Mr Aitken said: "If we are to help young people understand the world in which they live, they need to experience the effects of religious faith on decision-making, and that means knowing what it is to worship." Catholic schools had the freedom to be more explicit about their value system.
The Scottish Executive is set to reveal its plans to reform religious observance early next year. A committee chaired by Anne Wilson, education director in Dundee, will recommend the removal of observance "of a broadly Christian character", an amendment to previous practice inserted by Michael Forsyth in his years of influence at the Scottish Office.