FAR from becoming more set in one’s ways, I’ve always thought one of the hallmarks of adulthood is having the maturity to question the things you take for granted.

Being able to stand back and reassess your views, particularly as new information emerges, even when it is tempting just to go along with what you have always believed, is the grown-up thing to do. It’s not easy, but it usually turns out to be the right thing, too.

Nations as well as people can lack the maturity to do this, of course, as the response to those who challenge the status quo often shows. And if some of the reaction to even the premise of historian Sir Tom Devine’s new book is anything to go by, Scotland still has a lot of growing up to do.

Called The Scottish Clearances, this ground-breaking 400-page volume not only adds to our understanding of the events of the 18th and 19th centuries north of the Highland Line, but sheds vital new light on how dispossession affected the rest of Scotland.

Read more: Historian Sir Tom Devine on what really happened during the clearances

Indeed, the book, which took its author much of the last 40 years to research, rewrites history by demonstrating that the scale of land loss and landlessness during the period was actually greater in lowland than Highland Scotland. The book comes out this week and I urge anyone interested in Scotland - either now or in the past - to read the full scope of Sir Tom’s discoveries and conclusions on this emotive topic.

Why don’t we know all this already? Sir Tom argued in an interview published in The Herald over the weekend that the collective memory and trauma of the Highlanders travelled and lived on with them wherever they settled. No such process happened for the lowlanders. He also believes mythologised, romantic narratives such as John Prebble’s best-selling 1963 book on the subject allowed the dissemination of a single and accepted truth that has been exploited by political and personal agendas ever since.

My own reading of the book has challenged but also transformed my thinking on the modern nation we live in today. I believe the loaded term “Highland” clearances is now outdated to say the least: from what I can see we must surely now refer to the “Scottish clearances” and begin to accept and recognise the different, more complex truths that flow from this.

Read more: Sir Tom Devine on what really happened during the clearances

For me, the fact that one of Scotland’s most eminent historians has laboured his way through hundreds of years of evidence to help us better understand ourselves and our nation should be celebrated. Not everyone agrees, of course, as some of the grimly fascinating online reaction to the interview makes clear.

I saw and contributed to some lively debate on the book’s central arguments. But there was also a strange and surprising reluctance among some – including many who really should know better - to accept that historical narratives can or should change at all.

Perhaps most frustratingly of all, much of the criticism from those unwilling to accept the armour-plated conclusions of the book (despite not having read it), took the form of vitriol towards the author.

“A typical Lowland Scotch historian who hasn’t taken the trouble to learn Gaelic” said one online critic. Another suggested Sir Tom is a “provocateur” who oozes “the resentment of the Edinburgh classes”. Yet another called him the “victors’ historian”. There was also in some quarters a rather bizarre conflation of criticism of the central argument about the lowland clearances with the fact that he accepted a knighthood.

Such an unwillingness to separate the message from the messenger is immature. But it’s also deeply worrying.

Not that the Lanarkshire-born historian, who is 73, will be surprised to hear his work has ruffled feathers. He fully understands the pull of romanticism that accompanies any discussion of Highland history. As the author of definitive texts on the Scottish diaspora and Scotland’s contribution to slavery, however, he also believes the country has grown up over the last few years and is more prepared to face and embrace new home truths, even if they are not flattering, or don’t fit with the old stories we tell ourselves.

Read more: Sir Tom Devine on what really happened during the clearances

I hope he’s right, but I am becoming increasingly concerned that as a society we seem more willing than ever to shoot the messenger, especially when that person deigns to be an “expert”. Indeed, at a time when experts are being rejected, harangued and rubbished - sometimes even derided as the enemies of the people - knowledge gained on hard graft and hard evidence becomes more important than ever.

This anti-intellectual backlash is widespread, as the dangerous populist rhetoric surrounding Brexit and Trump attests. I get that when times are uncertain and grim it can be comforting to hang on tight to the old norms. But being an adult requires resistance to the adolescent, Trump-esque urge to shout “liar” or “conspiracy” whenever we hear something we don’t like. Come on Scotland, let’s face the reality of our history. And let’s not shoot the messenger.