The writer Robert Louis Stevenson came to Samoa for the sake of his health.

Having suffered from tuberculosis throughout his life, the warm Pacific air made him feel alive again. He was given the native name 'Tusi Tala', a teller of tales, and indeed he produced some of his most Scottish books, including Weir Of Hermiston, under the shade of tropical trees. But in 1894, aged 44, Stevenson died of a cerebral hemorrhage.

He had asked to be laid to rest on the plateau of Mount Vaea, visible from his home, Vailima, and the day after Stevenson's death some 40 Samoans, including native chiefs, began the seemingly impossible task of clearing the virgin jungle up the mountainside. Last week I trekked for half an hour along the path they created and spent a while by the writer's simple tomb. On one panel was his poem Requiem, with its premonition of death under a wide and starry sky.

'This be the verse you grave for me,' begins the second verse, 'Here he lies where he longed to be.' I'm not an emotional person but I found the experience quite moving; since I had arrived in Apia a few days before it had not stopped raining, but for three hours on Friday morning it relented, giving me enough time to pay homage to another Edinburgher who strayed far from home. Stevenson's house, now a museum, was full of reminders of my native city, and indeed Scotland.

During his time on the island Stevenson became something of an agitator for Samoan self-determination, championing the rights of a people caught between German, British and American would-be colonists. A staunch Unionist at home (he planned, but did not complete, a history of the Act Of Union), Stevenson risked deportation and the displeasure of his contemporaries by firing off angry letters to London newspapers.

Nearly 70 years after Stevenson's death, Samoa became the first Pacific nation to stand, as one taxi driver proudly told me, 'on its own two feet'. 'Samoa is founded on God' reads a simple independence memorial opposite its legislative assembly, and while the local newspaper bemoaned widespread corruption, half a century later it is a relatively prosperous and democratic country. But colonialism is not dead in this part of the world: the US still controls its own slice of Samoa and, further west, sits the French 'collectivity' of New Caledonia.

It is important to remember that Samoa, along with dozens of other former protectorates, mandates and colonies, won independence from the United Kingdom of Great Britain and Northern Ireland rather than just 'England', something conveniently glossed over when First Minister Alex Salmond speaks of the United Nations beginning with just 50 members in 1945 but more than 190 today. This implies some equivalence between post-war independence movements and that in Scotland, which of course does not stand up to much scrutiny.

In his foreword to Your Scotland, Your Referendum, Mr Salmond conceded Scotland was 'not oppressed' and had 'no need to be liberated', although on a 2012 trip to Dublin he could not resist drawing an analogy between Scotland and Ireland, saying the latter well understood that 'bullying and hectoring the Scottish people from London ain't going to work'. It took the former SDLP leader Seamus Mallon to remind Mr Salmond that Scots had been 'part of the bullying that took place in Ireland' from the Ulster plantation until as recently as the Troubles.

As the Princeton historian Linda Colley writes in a stimulating new book, Acts Of Union And Disunion, the Empire was British, 'but it was also Scottish, in some colonial locations - such as Hong Kong - almost overwhelmingly so'. And those who moved into 'this unwieldy, grasping construct' as administrators, soldiers, adventurers, missionaries and professionals 'mirrored the mixed and precociously multicultural nature of the United Kingdom itself'.

This has always been something of an inconvenient truth for some (usually fringe) Nationalists, who sincerely believe Scotland's experience is akin to that of an exploited colony. But in seeking to depict Scottish independence - as the party leadership often does - as part of an ongoing, and almost inevitable, decolonisation process, they avoid another uncomfortable reality: that the secession of one part of a modern, democratic welfare state from the other is unprecedented. Quebec came close in 1995, but that's your lot.

As the historian Eric Hobsbawm observed in his critique of Tom Nairn's 1977 book, The Break-up Of Britain (which also bought into this narrative), in fact 'the great bulk of the new states since 1945 have not arisen by the division of existing states, but by the formal separation of already separate dependent territories, within pre-established frontiers, from their metropoles'. Scotland, of course, was an intrinsic part of the British imperial metropole, and in certain parts of the Empire - as Colley has observed - the dominant one.

Now Mr Salmond is, like Robert Louis Stevenson, a teller of tales, and often beguiling ones at that, only this is not one of his most compelling. In reality, (and contrary to Linda Colley's curious impression) Scots do not feel 'colonised' by England and do not view independence as inevitable. Possible, certainly (an important yet seldom-noted psychological shift), but still a little bit scary. Again, compare and contrast with former British colonies: where referendums were held, there was generally an overwhelmingly Yes vote.

Malawi did not need a White Paper to convince its voters to back independence, and Zambia did not need a three-year slanging match between official Yes and No campaign groups to help it reach a decision. And rarely did the UK seriously resist the clear will of various peoples to split with the motherland, indeed the Anglo-Scottish Iain Macleod got flak from Tory die-hards for encouraging the wind of change to blow as quickly as possible through the African continent while he was Colonial Secretary.

Of course there were exceptions, and it is curiously fitting that 2014 should begin with the Anglo-Scottish Union reaching a crisis point just as the British-Irish one did in 1914. No one could pretend that Britain's handling of the Irish Question was a model process, although it is being a little more flexible this time round. But then the 1801 Act Of Union never gelled in Ireland as the 1707 one had in Scotland. It had its own island story, its own settled will to go it alone.

Island stories, as Colley also muses in her book, can be very potent, and of course Wales and Scotland are as much part of the 'British' island story as England. After all, a large part of the British Empire comprised islands, serving to, in Colley's words, 'multiply Britain's own island stories and render them a worldwide phenomenon'. A few even remain, such as Bermuda and the Falklands, now restyled, rather blandly, 'British Overseas Territories'.

But Scotland, unlike Ireland, can't posit its own island story, thus the often-contradictory emphasis on utilitarian goals and financial gain. It might not be enough; what was it Robert Louis Stevenson said? 'Little do ye know your own blessedness; for to travel hopefully is a better thing than to arrive, and the true success is to labour.' Not a bad summary of where the SNP might find itself in 10 months.