Like all platitudes, a little platinum is sprinkled with the dreck. Knowledge can indeed become divorced from ordinary concern and conversation. This can be because the lecturer, for example, is financially well-off, works alongside ideological clones, or simply because narrow specialisation rules out broader wisdom. There can also be the expert's conceit, which mocks foreign perspectives: the huffy humanities student whose nose wrinkles at mathematics, for example. Prejudices against science are then strengthened by selective reading, which puts the ''con'' back in ''confirmation bias''. But these pathologies are not unique to the academy. Many bankers are more aloof from ordinary cares than philosophers, and equally sunk in ideological clay. And plenty of tradesmen forgo a broader worldview in favour of myopic expertise. ''Christ, plumbers are stupid,'' spits the sparky. Mandarin's alienation, snobbery and blinkered narrowness are not the monopoly of academic bookworms.

And importantly, reading can actually compensate for the inevitable rigidity and pettiness of adult life. We cannot necessarily live through wartime grief, psychological fragility or rapacious humanity's looming Armageddon. But we can gain some insight in the pages of Hemingway's A Farewell to Arms, Charlotte Wood's Animal People or Ragnarok by A. S. Byatt. Likewise for scientific studies. Judging by my own suburb, I might think Australia is everywhere quiet and polite, with good public transport, parks, and schools - but reports on geography and socio-economic class suggest otherwise. Put simply, read with an eye for the limitations of art or research, written stories and essays are not a fast-track to aloof distraction. They can compensate for, and sometimes overcome, our mortal smallness.

The philosopher A.N. Whitehead once remarked that good philosophy is like plane flight - one might say the same of all keen thinking. Speculative flights put the ground in sharp perspective; they give us distance and new perspectives. But we have to begin and end each ''flight'' with the solid ground of experience, to orient ourselves and act on a human scale. Likewise for the relationship between first-hand knowledge and abstract analysis, practice and theory, fantasy and immediate fact.

For example, I recently wrote a column on obesity. I know what it is to be overweight; I can understand many of the hurdles that one tries, perhaps breathlessly, to vault. However, knowing what it feels like to be dangerously overweight does not ease the dangers of diabetes or heart disease, or suggest that one's size is a fine ambition. In fact, I suspect that being overweight can, over the years, make one's condition seem more essential and valuable than it is.

The ideas gained from continued experience of obesity make the healthier ideas seem weaker. In a quirk of human intellect noted by philosopher David Hume, slimness or elegant muscularity, for example, are eventually less believable. To overcome these prejudices, information from scientists, nutritionists, doctors is a good start. They might be dry or dull, but they remind us of the dangers of what's so comfortably ''normal''.

In other words, experience does count, but it is also a source of bias, dumb habit, and false foundations or generalisations. If it is the heart of knowledge, it is by no means the only organ. It must be stitched to one's own critical rationality, and others' insights and impressions. We don't just need experience, we need experiences, and not just our own. And these are often best preserved and discovered in the written word.

Put this way, attacking ''book learning'' is often nothing more than a smug consolation, luxuriating in the well-worn bedclothes of prejudice. When confronted with challenging logic or facts, one dismisses them with the verbal equivalent of covering one's eyes with the blankets. Time to wake up.

Dr Damon Young is a philosopher and the author of Distraction: A Philosopher's Guide to Being Free.