Whilst still whole-heartedly backing a Yes vote for independence in the looming Referendum, the polymath author of Lanark, at an event at the Edinburgh International Book Festival, said pledges of more powers for Scotland in the event of a No vote were "wonderful".
At the event, he also re-iterated his criticism of Scottish boards appointing English figures to senior positions in the arts world.
On the referendum, he said: "One of the reasons I am feeling quite optimistic is that I have been reading the publicity of the No campaign.
"It was very interesting because they said there would be fuller employment, more investment in public business, several things that I thought 'surely this is not on the Conservative agenda?'
"But a good friend told me that the No campaign having been criticised for having no positive ideas, is actually promising a greater degree of independence to the Scottish Parliament if we vote No."
He added: "Wonderful. A small step forward, and I want a bigger step forward of course.
"This will be the third referendum, and at each of the past referendums, the vote for Scottish independence has increased.
"There is certainly going to be a bigger proportion for it [in September] and I hope its big enough to carry, but even if it doesn't, if the present Government [in Westminster] does carry through its promises it is still a step nearer to what I would finally like to see."
Gray, whose original artwork was used by the Sunday Herald on its front page when it formally launched backing for the Yes campaign earlier this year, said he did not know how the vote would go but "things were interesting."
He read several passages from his latest book, Of Me and Others, at the event.
Gray said artists had a role to play in the independence referendum campaign, but added: "Artists are no more important than labourers, trademen skilled and unskilled.
"I think writers tend to be as big mouthed as journalists, although journalists are writers too.
"And politicians, even politicians should have a say in this matter."
Of Creative Scotland, Gray repeated previous criticisms of how those in leading positions are appointed.
It was an issue he tackled in his controversial essay about "settlers and colonists" in the cultural sphere in Scotland.
"We have got a vast industry of Scottish arts administrators," he said.
"And of course they need a few artists to take the bare look off them.
"I have been accused of hating the English - which I don't, I don't hate anybody - for pointing out that the people in important Scottish committees, by which I mean bankers and businessman [on boards], prefer having English people in charge of Scottish arts.
"That's why they chose an English person to be in charge of Creative Scotland.
"I promise you it's the Scots who are to blame, because they don't the idea of Scottish writers and painters in charge of their own institutions - impossible."