Reading Shuggy's doubts about whether Scotland really is left-wing and James Forsyth's account of Tory divisions, I was struck by a common theme - one which also links with Douglas Carswell's defection to Ukip.

The theme here is a longstanding division within the Conservative party, which we might call that between the optimistic and pessimistic traditions.

The pessimistic traditon - which I associate with Oakeshott (pdf) - is wary of change, seeing it as deprivation, whilst sceptical of those offering political programmes, fearing that they over-estimate the powers of government rationality and under-estimate the law of unintended consequences. The optimistic tradition, on the other hand, believes that change - often in the direction of free markets - is both feasible and desirable.

This, for example, was the division between Thatcherites and "wets". Wets thought the best they could do was accommodate themselves to social democracy and achieve managed decline for the UK. Thatcherites thought free markets would unleash an economic renaissance.

It is also the division within the Tories over Europe. Optimists think we are better off out whilst pessimists see the EU as flawed but fear the disruption of leaving and so seek to tweak its imperfections.

The division isn't always so clear. I'd characterise the Cameron government as a mix of both. Its belief in free schools and expansionary fiscal contraction are optimistic, whilst the general lack of legislative optimism betokens pessimism. I'd even suggest that Thatcher was a mix of both: her reluctance to reform the NHS, for example, reflected a scepticism about the limits of what she could achieve.

This, I think, helps explain Carswell's defection. His political programme - direct democracy and much smaller government - puts him on the optimistic end of the spectrum. Small wonder that he felt unhappy with the (often) cautious pessimism of Cameron.

And this is where Scotland comes in. Shuggy writes:

[The SNP] have not enacted one single redistributive policy in the last seven years...Some sharper nationalists have been candid enough to acknowledge attitudes to the welfare state in Scotland are an indication of our conservatism as a nation, at least as much as our supposed socialism. There's a whole bunch of people going to vote Yes because they want things to stay the same, not because they want change.

This reminds us of an important point. Scotland has not always been anti-Tory. Before the 1980s, it often voted heavily Conservative. This, I suspect, was because the Scots have long had a big tradition of gloomy melancholic scepticism which was comfortable with the pessimistic strand of Conservatism. Scotland turned anti-Tory - and nationalist - when that strand was overpowered by a Thatcherite and post-Thatcherite free market optimism.

You might wonder why I'm saying all this; why should I intrude into the private grief of Tory unionists?

Simple. I am sympathetic to the Oakeshottian pessimistic tradition, and fear that its eclipse is a costly one. The divisions within the Tory party, and the possible break-up of the UK, show that those costs are even more widespread than I'd imagined.