Lately, as I follow American politics, a question keeps nagging at me, resurfacing unbidden in idle moments over coffee, or while waiting on station platforms: what is Donald Trump thinking?

To be clear, I don’t mean “what makes Trump think he can be president?”, since for all I know, he doesn’t really think this.

And I don’t mean “what makes Trump think the right way to campaign for the presidency is to travel the country by private jet spewing racist bile about Mexicans every time he opens his mouth?”

Clearly, Trump either believes that stuff or is cynical enough to pretend that he does.

No, I mean the question straightforwardly, even naively: what is it like, the inner mental world of Donald Trump? Inside his mind — just behind those often-narrowed eyes, just beneath the unquestionably natural hair — what does it feel like to be him?

This question is so jarring, I think, partly because we so rarely think of any internationally famous people — even the non-preposterous and non-obnoxious ones — as possessing internal lives. (What is Barack Obama worrying about, as the water from the shower courses down his back? What runs through the Pope’s mind, in the seconds before he drifts to sleep?)

And partly, it’s jarring because Trump represents something so purely archetypal in the American psyche — wealth, or anyway the appearance of wealth, as the pinnacle of human meaning — that it’s impossible to see behind the facade. But there must be something behind the facade. (Right?) And so, to paraphrase the philosopher Thomas Nagel, whose landmark 1974 paper ‘What Is It Like To Be A Bat?’ probed the difficulties of ever understanding the conscious experience of life-forms sufficiently different from ourselves...

Well: What Is It Like To Be A Trump? I’m not the first to wonder. In 1997, the veteran New Yorker writer Mark Singer wrote a characteristically brilliant profile of Trump, who comes across as a lonely figure, isolated at the centre of a self-built prison of luxury.

I tend towards this explanation for Trump’s apparently missing soul: that there’s lots going on in there — anxieties, insecurities, feelings of inadequacy, panicky efforts at self-soothing through attacks on others — and that Trump has absolutely no intention of letting anyone else see it. Ever.

My professional psychological qualifications for making this kind of remote diagnosis are, I should emphasise, non-existent. But I’ve long been struck by the insight of the Jungian analyst James Hollis that nobody ever does “crazy things”; every behaviour in which we engage makes some kind of sense, once you “understand the emotional premise”.

Everything Trump does is in service to some logic, presumably learnt in childhood, according to which it’s what he had to do in order to feel OK. The logic might have been flawed; it might have stopped working long ago; it might inflict suffering on others. But it’s a logic all the same: some inner hole is being filled; some demon’s being escaped.

What hole, specifically, in Trump’s case? I’ve no idea, though it doesn’t take a genius to read of his upbringing as the son of a major real-estate developer and guess at the lessons he might have learnt about business success as the sole measure of self-worth. And be honest: if you got to the pinnacle of American business celebrity, then realised the empty feeling still hadn’t gone away... wouldn’t you start scrambling for an alternative, for example a run at the White House?

The problem with thinking about people like Trump in this way, especially if you’re a dispenser of liberal opinions, is that it becomes suddenly much harder to deride them. (I don’t, of course, mean that his opinions become any more palatable.) Because to some degree don’t we all spend our lives projecting our insecurities outward?

Isn’t it only accidents of birth — luck, parenting, a middling level of privilege — that mean I’m not projecting mine in as high-profile or as damaging a manner as Trump? The difference is only of degree.

“Presidents and pontiffs parade their neuroses at the expense of the rest of us,” writes Hollis. But the neuroses themselves are pretty universal.

Empathy for Donald Trump, a man who — among his many other evident faults — by all appearances possesses no empathy for others is a pretty unnerving feeling, I can tell you.

Let me banish it swiftly, then, by recounting what happened after Singer’s profile was published in an anthology. (He recounts the story in this video.) The book was reviewed in the New York Times, triggering a disparaging letter from Trump, which boosted its Amazon ranking. Singer decided to send a wry thank-you note, with a gift: “I thought, what does he like? And I realised, money. I’m going to send him some money. I decided to send him a thousand dollars. And then it occurs to me... I don’t have a thousand dollars. So I came up with another figure. I wrote him a letter: ‘Dear Donald, thank you so much for that wonderful letter to the New York Times... I enclose a cheque for $37.82, a small token of my gratitude. You’re special to me. Also, I enclose two Band-Aids because you seem unable to stop picking at this particular scab’.”

A few days later, the letter was returned, with an insult scrawled on it from Trump.

But here’s the part of the story that sends me straight back to psychoanalyzing Trump, a temptation I seemingly can’t resist no matter how futile the effort always seems to be: the cheque was gone. For whatever mysterious inner reasons — a desperate neediness that makes him grab anything he’s given? A clever sense of humour? Sheer avarice? — Trump had cashed it.

Guardian News & Media Ltd, 2015