There were seven of us at the bar last night, and the bill came to $90.37. We left $100, which amounts to a tip of just over 10%. Out the door we went into the streets of New York.

Across the street, we were chatting before going our separate ways. Suddenly the waitress was there, having run across the street after us! We hadn’t paid properly! She showed us the bill for $90.37 and the $100.00 we had left and explained that this wasn’t good enough, a tip of 18%-20% was customary.

[16 September 2014]

The other day I managed to take notes on a stretch of my stream of consciousness, put salt on its tail. Why am I thinking of asking Kate about Judas’s betrayal of Jesus, I asked myself? I worked backward till I had figured out the chain.

Biking to work, I passed a woman in Indian clothes. That got me thinking about the rape problem in India, which the new prime minister Modi is fighting. How silly it would be if an Indian claimed that the reason for the rape problem is that Indian men have stronger sex drive than others, hence India’s big population! China has grown more slowly, yet China is strong and India is weak; there’s so much more to the power of a country than the size of its population. Britain, for example, was small when it ruled the world in the Victorian era. Remember that headline from the good old days, “Storm in channel, Continent isolated”? But they say the headline is apocryphal. What about this word “apocryphal”? It alludes to the Apocrypha, but where does that come from — is it Greek for “alongside-writing”? The Gospel according to Judas is apocryphal, but something has bugged me about Judas. If Jesus was such a notorious rabble-rouser, why did the Romans need to hire somebody to point him out? I must ask Kate; maybe she will know.

All this happened inside my skull between Meadow Lane and Donnington Bridge, where I stopped the bike and grabbed my notebook.

[31 July 2014]

Jacob and I were discussing material possessions yesterday. To reduce stress in this busy age, should you get rid of almost everything? I realized that for me, such minimalism is not the answer. For me, contentment differs from stress by a very practical factor of 2, which I summarize in this personal version of the Micawber principle*: Drawers half-full, result happiness. Drawers overflowing, result misery.

What goes for drawers and cupboards applies to time, too. If all your hours are scheduled, you’re miserable, but if half your hours are scheduled, you’re stimulated. I don’t want empty drawers and I don’t want empty days. I want plenty of life and plenty of possessions. You just have to keep on top of that factor of 2 to make sure you are the master, not them.

*From David Copperfield: “Annual income twenty pounds, annual expenditure nineteen pounds nineteen and six, result happiness. Annual income twenty pounds, annual expenditure twenty pounds nought and six, result misery.”

[27 July 2014]

When I’m biking, I get aggravated by pedestrians who step into the road without looking and cars that drive into the bike lane without caring.  One day a pedestrian or a car may knock me innocently down.  If they knock me into traffic, I could be seriously injured or even killed.  I feel angry at the stupidity of these dangerous and irresponsible people.

There is something ugly here. Honesty compels me to admit that there’s a part of me that hopes the other guy will misbehave.  If he misbehaved a bit in the last block, I watch eagerly, expecting and secretly hoping he’ll do something even more outrageous in the next block, thereby vindicating my judgement of him as as bad person.  There’s even a part of me that imagines it might not be too bad if an accident happened. Maybe this is the impulse toward martyrdom.

But mostly it’s about ego of the more quotidian variety.  The worse the other guy is, the clearer my superiority. Ugly.

[13 July 2014]

I bought the beautiful second edition of Horn and Johnson’s Matrix Analysis at the SIAM meeting in Chicago last week. This morning I biked in to the office with the book in my bag, looking forward to adding it to my linear algebra collection.

But I had an uneasy feeling. Was it possible I had already bought this volume earlier, and forgotten? It was a relief to reach my office and find that no, it wasn’t already on the shelf. I didn’t own two copies.

Curious, eh? Given a choice between owning two copies of a fine book and just one, I preferred the latter.

[14 July 2014]

Teenagers have always been healthy and beautiful, even in ancient times. But in those days, youth didn’t last long. By 25, the beauty was gone, and by 35, you were old.

Then along came miracles of modernity, and for many lucky people man’s five years of beauty extended to ten, twenty, thirty. Health and vitality became not just a phase but the normal condition of adulthood.

I’ve just spent a week in heartland USA. I saw that teenagers are sexy, just as they have always been. By age 30, though, most of them have sizeable bellies, and a fair fraction are obese. Years of hamburgers and donuts add up, and by age 40, these people are out of the game. Youth is becoming fleeting again.

[30 May 2014]

In America, they say, garages are so big that people store cars in them! Here in England, of course, that hasn’t been the pattern for years. But though our garages are too small for cars, they’re great for tools and workbenches, making perfect male caves. My father-in-law wouldn’t know what to do without his.

We puzzle how the eye could have evolved by natural selection. What use was the first step along the evolutionary path to an eye? You just have to remember that evolution took twists and turns on its way to the present, and if your cave seems too good to be true, it may have originally evolved for quite another purpose.

[8 May 2014]

My life is driven by dual aims: to be conscious, and to be unconscious.

Oh how deeply I want to be conscious! I want to perceive, to understand everything. At heart I believe that if only my perception were complete, I would save my soul and save the world.

So I strive constantly to be hard-working and efficient to make time for those higher perceptions. But isn’t it curious how often my tactic for achieving efficiency is to try to make things unconscious! To get things done without a murmur and without an error, it’s all about  habits. The keys go there, the phone goes there, this and that and a thousand other schemes unthinking. My conscious self would have no chance of maintaining the required level of performance. To exalt my consciousness, I am constantly striving to shift the clutter of my life into the unconscious territory.

[30 December 2013]

A grande cappuccino costs £2.40 at Starbucks in Oxford, but on arrival in Geneva, I found the price here is £4.60 (6.80 Swiss francs).  Swiss prices are sky-high, and for a week or two, every time I bought anything in this city I had a painful sense of money slipping through my fingers.

Two weeks later, I had mostly stopped feeling the pain.

On the face of it, there’s irrationality here. Either I was irrational to be so disturbed by the high prices originally, or I am irrational to be so blasé about them now. Which is it, then?

And yet, maybe the deeper rationality consists precisely in being disturbed at first and less disturbed later. Changes in our environment may bring danger, and we must be vigilant in detecting and responding to them. Yet these costly cappuccinos will not break my bank account, and one must get through life. If you’re alert to everything, you’re alert to nothing.

[22 February 2014]

In a spectacular breakthrough, Yitang Zhang proved that there are infinitely many pairs of primes differing by at most 70 million.

This is the opening line of the advertisement for the upcoming LMS-CMI Research School on Bounded Gaps Between Primes.

[16 April 2014]