It wasn't supposed to be this easy. Navigating a menu with the author of The Virtues of the Table: How to Eat and Think should have been arduous. I had imagined agonising indecision and hand-wringing; but instead I got a snappy: "It's merely a matter of working backwards from the Eccles cake and cheese. I'll have the brown shrimps with white cabbage and the kohlrabi."
My mistake was letting Julian Baggini pick St John, that bastion of British loveliness, which lives and dies by its ethical dishes. Baggini's recent conversion to "conscientious omnivore" meant he didn't even have to avoid St John's famed devilled kidneys or roast bone marrow; it was more that he knew the modest shrimps would leave enough space for that all-important pud. And, being a philosopher, he is all about problem solving.
With his latest book, Baggini, 45, tackles the biggie: food, because it "grounds us. There is nothing more basic than the need to eat and drink". Thus, he dishes up a philosophy to "eat, drink and live by". I guess it was too much to hope he would be a menu ditherer. Over a glass of claret (him) and a beer (me), as we tuck into some sourdough, he reassures me that anywhere else he would have put the waiting staff through their paces.
"It can be quite amusing sometimes to ask them about meat. You don't want to be pompous but I sometimes ask in a light-hearted style, 'On a scale between haven't-a-clue and know-them-by-name, what do you know about your animals?' It can backfire because they just don't understand, or think you're mad. The other day they just looked blank."
It's all very Portlandia, I say, referring to the ironic US sketch show that spoofs earnest foodies in Portland, Oregon, unable to order the chicken without seeing its birth certificate. "It's very easy to be parodied," agrees Baggini, but there are serious points to be made. "I think we should ask these things. Actually, it's quite strange that there are people who, when they go to the supermarket or their local shop, will always look at a label but when they go to a restaurant they don't bother. It's only by asking that people realise customers care and change their policies."
In Baggini's world, there's no just-playing-the-vegetarian-card. His chapter on "killing with care", which describes him taking a friend's pigs to an abattoir, has me spluttering over my breakfast when he states that "welfare-based vegetarianism is the most incoherent ethical stance on animal welfare you can take", mainly because milk drinkers are signing bull calves' death warrants. Veggies are, he concedes, at least better than those with no qualms about animal welfare, who eat what they like.
There's danger, though, in taking it all too seriously, and he reckons the odd bit of meat shouldn't be the end of a vegetarian's world. "I think there's a superstitious idea that by coming into contact with something you're somehow contaminated or automatically implicated in any harm that's caused by it. If you're basically eating conscientiously but make a mistake, I don't think that makes you morally culpable."
There is more good news, too, for those who find the constant foodie mantra of "small is good; big is bad" exhausting when trying to refuel. Baggini finds virtues in the least likely places, from McDonald's to Nestlé. And he doesn't buy the localism bias that has made shopping at a supermarket such a dirty pastime for some. A Golden Arches lunch date would have been a good call, in retrospect, because its menu merits a little tip-toeing around: anything with eggs gets a tick, because they're all free range, though the chicken is not.
He thinks the fact that "a lot of Michelin-starred restaurants serve Nespresso [Nestlé's imitation-spawning, capsule coffee creation] is extremely surprising," explaining that it's all down to consistency and freshness. That said, he prefers using a filter at home, which, for the past eight years has been Bristol. He lives with his partner, Antonia Macaro, whom he describes as a "non-practising psychotherapist". The pair write a weekly Financial Times column, "The Shrink and The Sage"; no prizes for guessing which is which.
He admits that he does do a lot of shopping locally, despite believing in the "interdependence" of global trade, especially when it comes with a Fairtrade label. He would pick his local Waitrose over Sainsbury's or Tesco, but insists there's nowhere he wouldn't shop. At Tesco, though, "you get what you pay for". He saves his opprobrium for a local health food shop "peddling very expensive cures which almost certainly don't work", something he finds "morally objectionable". "The idea that little local companies are perfect is mad."
If this all sounds terribly middle-class, you're not wrong – especially as Baggini, a grammar school boy from Kent, is nothing if not earnest in his delivery. But he reasons that most of us could think more about what we're eating, especially now he's written a blueprint. Of course, he wouldn't "blame anyone for buying the cheapest food available and not having time to think", but he reckons: "There's something kind of odd about sticking up for the rights of people who are worse off to buy cheap food at the supermarket when what makes that food possible is other people, even worse off, in other parts of the world, being exploited."
By now, the main courses have been polished off, and the Eccles cake has arrived, complete with a giant slab of crumbly Lancashire. I'm regretting being abstemious; that'll teach me to ignore Baggini's early admonition that it's pointless to worry about what you choose in a restaurant – provided you don't eat out too often, of course.
Cooking-on-a-budget leads to talk of the food blogger-turned-campaigner Jack Monroe, who is a genius at magicking meals on a shoestring. Baggini is a fan, but he cannot help noting that "animal welfare doesn't always come into it" if you're opting for something like Tesco Value cream cheese. "[It's easy] to ask people only to eat animal products when animal welfare standards are high if you don't like a lot of meat or can afford to spend a little extra," he adds.
He is interesting on the subject of cooking to instruction: his book is studded with non-recipes, basic how-to guides to everything from hummus to a simple tomato sauce. "There's a sense in which recipes are part of the problem and not part of the solution. If all the time [people are] thinking that to cook a dish they need a recipe, they're not really learning how to get a feel for food and knock up something tasty."
Next up for this master of popular philosophy – he has even had a cameo in two of Alexander McCall Smith's Sunday Philosophy Club novels – is something a little deeper: a book about free will. He's not knocking the philosophy publishing boom, but reckons there is scope for some volumes with a little more substance.
"There are any number of titles that are variations on how philosophy can help you live your life better. Well, fine; but I think it's about time really that we had a bit more."
Despite the heavy pontificating, lunch with a philosopher was a great deal lighter than I had envisaged, but next time I'm giving him something more challenging to philosophise about. Tesco's in-store café might be a good place to start.