This is a fun thought-experiment highlighting the challenges of communicating over an unreliable channel — where your message may or may not get through, and where you won’t know if it has.

The situation is that two armies, either side of a hostile valley, are trying to coordinate an attack, and they want to attack at the same time to be sure to succeed. The trouble is, to coordinate they have to send brave messengers through the hostile valley to the other camp and the messengers may or may not be captured along the way.

To coordinate the attack you have to know that your message got through which you’d know if you received a confirmation. But how would the general sending the confirmation know that their confirmation got through unless they received a confirmation of the confirmation. And on…

The two generals problem

The law of diminishing returns: at some point, doing more of the same stops paying off like it used to.

You might think that adding more of a good thing would make things better. And, yes, that’s often true, up to a point. However, the law of diminishing returns suggests that as you add more of a single factor, you are likely to yield progressively lower benefits.

It’s like the old adage, “Too many cooks spoil the broth.” Another cook or two might help, but beyond that, they’ll probably start getting in each other’s way. Aside from cooking broth, you might see the law play out in spending on advertisements, quality improvements in production or your wealth.

And we should also never forget that “more is different”.

The sketchplanation is an homage to perhaps my favourite comedy sketch with an early-career Simon Pegg in the series Big Train: The Cake Factory (video). Well worth two and a half minutes.

Also see: the law of diminishing brownies

I updated this sketch for the release of Big Ideas Little Pictures. Here's the original

Law of diminishing returns

It’s easy to think “it’s just a few minutes.” But as the number of people that you hold up increases, the true cost of being late scales rapidly. Being 10 mins late to a meeting with 10 others is 100 minutes. Holding the door for 20s on a train of 600 people is over 3 hours of time collectively. Unless your time is worth a lot more than everyone else’s it’s worth thinking twice before holding the door to a train or not taking the start of a meeting seriously. I think, at the end of the day, it’s really about respect.

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The cost of being late