What's the difference politically between Nicola Sturgeon and her predecessor as SNP leader and First Minister, Alex Salmond?
According to one former adviser I spoke to recently Mr Salmond is "a cultural nationalist" and Ms Sturgeon by contrast is "an economic nationalist".
The point this ex-SNP aide was making was that the former First Minister would be more sympathetic to spending money on, for example, supporting Gaelic.
The current First Minister was said to concentrate solely on putting resources into areas which will stimulate economic growth - to take one current example, spending more on cutting business rates.
For Ms Sturgeon it is, then, "the economy stupid" to borrow a phrase from Bill Clinton's campaign team of a very different political era in American politics.
I have to say that I do not completely buy this distinction drawn by this ex-adviser between the SNP's master political sorcerer and his sorcerer's apprentice.
Mr Salmond was an oil economist to trade and spent a lot of time making the economic case for independence.
Remember his claim Scotland would join the 'arc of prosperity' of small successful independent nations including Ireland, Iceland and Norway?
That was before the great crash of 2008 which exposed certain economic weaknesses (to put it mildly) in two of those three countries. We've not heard much about the arc since then.
Then in the run-up to the independence referendum Mr Salmond made the case that an independent Scotland would flourish thanks to the substantial income coming in from north sea oil taxes.
Well that turned out to be problematic too as the price of oil plummeted subsequently, though it has recovered significantly in recent months.
However, if the distinction between Mr Salmond and Ms Sturgeon is not as clear as some would say there is something in the differentiation.
In the past when I interviewed Alex Salmond - long before he become First Minister - he spoke lyrically, and surprisingly sentimentally, about his aim of seeing the Saltire flying over an independent Scotland.
When I sat down for a start of year interview with Nicola Sturgeon, which you can see on Representing Border tonight, I asked her about recent comments by the SNP's deputy leader at Westminster.
Aberdeen MP Kirsty Blackman told the Guardian: “I don’t think most folk in their daily lives give two hoots about whether Scotland is a member of the Union. "The constitutional issues are not the biggest concern for an awful lot of people and, in fact, I very rarely talk about Scottish independence in the (Commons) chamber, because I talk about things that matter to the people of Aberdeen.”
Ms Sturgeon told me:
"Kirsty was making an argument I've been making all of my political life..."
After suggesting that I was "over-simplifying" Ms Blackman's position - I was quoting her directly - the First Minister explained what she meant:
"Independence is not some abstract constitutional argument. It's directly related to the day to day lives of people in Scotland.
So there you have it. And Ms Sturgeon's explanation makes the work of the SNP's 'Growth Commission', set up in September 2016 and led by former MSP Andrew Willson, all the more important.
The Commission's remit, according to the SNP, is to "assess the projections for Scotland’s economy and public finances, consider the implications for our economy and finances of different potential governance scenarios..".
It will make recommendations for policy on:
measures to boost economic growth and improve Scotland's public finances - both now in the aftermath of the EU referendum and in the context of independence.
the potential for and best use of savings from UK programmes in the event of independence, such as Trident.
the range of transitional cost and benefits associated with independence and arrangements for dealing with future revenue windfalls, including future North Sea Revenues.
Ms Sturgeon says the Commission report, which has now been a long time in preparation, is currently being "peer reviewed" which suggests independent academics are looking at its methodology and conclusions.
But it will be published soon we are told (perhaps soon-ish might be more accurate) and it will form the basis of the SNP's bid to build a new case for independence.
If it does address the issues of the public finances - official Scottish government figures show a £13.3 billion gap between spending and tax - and north sea oil revenue that case will need a while to build.
Which helps explain why Ms Sturgeon will not rule out calling for a second independence referendum this year, or indeed next, but does not appear very enthusiastic about the prospect.
Of course the Wilson Commission does not exist in a vacuum. There are other extremely important factors at play, particularly the uncertainty over Brexit, which the First Minister says is her immediate focus.
But when the SNP does come to calling another vote on independence - as the Ms Sturgeon says she will - a lot will rest on that assessment of the First Minister as an economic nationalist.
You can see my interview with Nicola Sturgeon on Representing Border tonight at 11.15pm.