As just about everyone in Scotland knows, there are now less than 100 days to go till decision day.

Will the standard of the referendum debate improve as September 18 gets ever nearer? I ask because two very different figures have intervened, emotionally, in the past few days.

First, the right-wing Tory MP David Davis - the man David Cameron defeated in the Tory leadership contest - has announced from south of the Border that the debate has not been nearly emotional enough. It has, he complains, been just about money. (I must admit that I know one or two people who get very emotional about money, particularly when they don't have it. That's not a sneer, it's a serious point.)

But my main reaction to his remarks was that he was being impertinent about a debate in which he had no direct interest. Then I realised he did have an interest, if not a vote; what the people of Scotland decide will have significant effects on the rest of the UK, and we shouldn't forget that. It's also true that his point had validity as the debate has, at times, descended into a rather crude auction.

A similar complaint was made at almost the same time by a totally different figure, the Scottish novelist John Herdman. Mr Herdman, unlike Mr Davies, does not often intervene in public discourse. He is a fastidious, well-regarded writer; to put it as sensitively as I can, his reputation is higher than his sales. He has been a committed and original Scottish nationalist for several decades. As far back as the late 1960s he was writing eloquently about the need for independence.

Mr Herdman reckons that the ongoing debate is characterised by "stupefying vulgarity". He is so disillusioned that he is beginning to worry that we, the Scottish people, may not be worthy of being asked the question that some of us shall answer on September 18.

Writing in a thoughtful but small-circulation literary magazine, he points to the principles, the commitments, the ideals and the sacrifices that other nations and peoples have made as they contended for their independence.

Similar thoughts have occasionally worried me. Other people across the globe have had to struggle and fight, and how, to gain their independence. Is what is going to happen here just too glib, too facile? But then I reject such notions, preferring to believe that it is a special and unusual privilege to be able to gain independence by means of a straightforward, peaceful, democratic process.

On the other hand, I do accept that the tone of the debate could be improved. Both sides seem, at times, to be appealing if not to actual greed, then certainly to the pocket rather than the heart or the mind. A kind of bizarre and mercenary contest is taking place, with the voters of Scotland being asked to calculate exactly how much better off they'd be by staying in the Union, or deciding for independence.

But before I dismiss this is as crass, which in some ways it undoubtedly is, I understand it is important to remember that many people in Scotland are living in poverty. Worst of all, many children are living in poverty. It is all very well to celebrate lofty notions of freedom and high principle. It is surely also necessary to talk about money.

Mr Herdman's main point, as I understand it, is that freedom is not divisible, and it cannot be bought. I'm sure that's true. But most of those who vote on September 18 will not be thinking in terms of freedom as such. They already are, to most intents, free. Many will be thinking, quite understandably, about their standard of living, and possibly also that of their children and grandchildren.

This may seem selfish, but think of it this way: is there any politician who would dare to say to the electors of Scotland: vote to stay in the Union (or indeed, for Independence) because it's the right thing to do, though it may well make you poorer? No doubt a few noble souls would respond positively to such an emotional self- denying appeal, But most of us now accept that politics is ultimately about, as Harold Wilson notoriously once said when trying to justify a devaluation, "the pound in your pocket".

There was a time when the SNP appeared to disdain arguments based on economic self- interest. That was before Gordon Wilson's magnificent slogan "Its Scotland's Oil". As the SNP changed from being a small party of protest to a large party of government, it had to develop from being a one-cause movement into a complex political machine that could, and therefore had to, win elections.

Meanwhile I believe there is a way to overcome the perfectly legitimate objections of David Davis and John Herdman. It's simply to point to the very considerable resources of Scotland, and their potential for good. Our land and yes, our gas and our oil, are often externally owned. There is absolutely no guarantee these owners are ever going to put Scotland's interests first, or even second or third, as they sit in their guarded palaces of steel and glass, making their hard calculations. If we do not have the control that comes with ownership, we will not be able to build a better society.

I could not pretend to understand all the ins and outs of the extended Grangemouth refinery dispute last autumn. But the resolution seemed to come down to the decision of one man, not a Scot or even a Scottish resident, who was certainly not directly accountable to anyone in Scotland. He may well be a brilliant entrepreneur and he has certainly made impressive amounts of money, but should he have had such immense individual power over a crucial Scottish asset?

I am not a socialist and I frequently (though increasingly with a heavy heart) defend capitalism, but the point here is that our future should not be driven by remote figures and indeed remote organisations, particularly when, as I noted, there are hundreds of thousands of children living in poverty, or near poverty, in our country.

Also, it does seem a bit cheeky of the No campaign to insist we'd be considerably better off if we remain in the Union.

The reality is that Unionist politicians have presided over financial crisis after financial crisis. The UK has a gargantuan national debt that should put fear into each of its citizens each and every day. You could say this appalling incubus is the real residue of 307 years of Union.

The second point is that UK governments have denied Scotland the proper fruits of our oil. It's often said, but it bears repetition: Scotland discovered oil and promptly became poorer. How scandalous that is. Our assets may not have been actually stolen, but they have certainly been squandered.

All this means that while the auction for votes may seem crass, it is in many respects understandable - and necessary.