Some information matters. Most information doesn't. Learning things that matter makes you smarter. Knowledge that doesn't matter is called trivia.

There is no absolute reference point for intelligence. Being smart is a competition against your age cohort. Trivia is the junk food of information. If you fill your head with trivia that means you're not filling your head with useful information.

Knowledge has a shelf life. Useful knowledge becomes trivia by going out-of-date. In theory, there is a spectrum between trivia and enduring wisdom. In practice, the distinction between trivia and enduring wisdom is binary because knowledge is distributed on a log scale. The shelf life of knowledge tends to be either longer than a human lifetime or much shorter than a human lifetime.

History tends to matter because history is curated. Hearing about something that happened 200 years ago is evidence that the the importance of the event has stood the test of time. Facts with a shelf life much shorter than a human lifetime constitute trivia.

How do you determine the shelf life of a fact?

Humans are mortals. The older we get the more likely we are to die (in the next year)[1]. According to Lindy's Law, immortals (like vampires) become less likely to die (in the next year) the older they get. A country or a language that has been around for a thousand years is more likely to persist for another thousand years than a country or language that was invented yesterday. The life-expectancy of a non-perishable thing is proportional to its age.

I like Linux/Unix because it so rarely changes. Unix was invented in 1969. It is 52 years old. I started learning Linux nearly ten years ago. Everything I have ever learned about Linux remains useful to this day. My knowledge of Linux grows monotonically. I expect my knowledge of Linux to remain relevant for as long as I can program computers.

I dislike Android/iOS development because it changes frequently. I first programmed an iPhone in 2015, around the time Apple released the Swift programming language. Swift is a superior programming language to Objective-C for programming most software on a modern iPhone. My older co-workers who learned to program in Objective-C had decades of accumulated knowledge rendered obsolete.

Apple changes their development toolchain so often that half my time was spent keeping my app up-to-date with Apple's rapidly-changing development environment. My knowledge of Apple software went obsolete as fast as I could learn it. The only durable fact I learned was "don't write native code for iOS".

Big companies changing development environments under their programmers feet goes all the way back to when Microsoft dominated the software industry.

The companies that do well are the ones who rely least on big companies and don’t have to spend all their cycles catching up and re-implementing and fixing bugs that crop up only on Windows XP.

Fire and Motion by Joel Spolsky, published in 2002

Want to get off the treadmill of learning a new IDE every decade? Code in Vim (or emacs).

Junk Media

New information tends to have a short shelf life because of Lindy's Law. Avoiding transient information like news, trends, intellectual fashions and so on makes you smarter. But it's also important to respond rapidly to major events like COVID-19. How do you respond to events like COVID-19 if you're ignoring the news?

I was aware of the threat a global pandemic for many years before COVID-19 existed. I started paying attention to COVID-19 when Wuhan was quarantined. I was keeping tabs on COVID-19 for months before it became a major news story in the USA.

Mass media has a record of misleading the public about where things are going. These were not failures of the system. These are examples of a propaganda system functioning as intended.

News Makes You Stupid

The day person-to-person spread of COVID-19 was confirmed in the USA I stocked up on emergency supplies. By that afternoon, I was figuring out how to profit off of it. My company was eight days ahead of the competition. By being first, we got all of the media attention. We were on national television and world news.

News is mostly noise. Only a tiny fraction of it is useful. News outlets are incentivized to tell you everything matters. They never say "nothing of importance happened today" even though nothing important happens 99% of the time. It's like how Facebook tries to find something to notify you about every day. If it's not going in the history books then it doesn't matter.

You can respond intelligently to world events by planning ahead. You should have a list of sudden events you're watching out for. Here are a few items on mine.

Responding to world events is like playing poker. You should play tight and aggressive. Playing tight means you ignore almost everything. Playing aggressive means you bet hard when you get that suited Ace-King.


  1. Except for a rapid gain in life expectancy shortly after birth. ↩︎

  2. Fukushima doesn't count unless you live in Japan. We're overdue for much worse. ↩︎

  3. What goes on your list depends on where you live. If you live in England you can ignore the threat of earthquakes. ↩︎

  4. Sometimes I respond to things that don't happen. I thought clubhouse might be a big deal but it wasn't. I also downloaded 抖音 well before it became popular in the USA under the name TikTok. That one did turn out to matter. ↩︎

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6 comments, sorted by Click to highlight new comments since: Today at 4:27 AM
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I like the framing of perishable vs non-perishable knowledge and I like that the post is short and concise.

However, after reading this I'm left feeling "So what now?" and would appreciate some more actionable advice or tools of thought. What I got out so far is:

  1. Things that have been around for longer are more likely to stay around longer (seems like a decent prior)
  2. Keep tabs on a few major event categories and dump the rest of the news cycle (checks out -- not sure how that would work as a categorical imperative, but seems like the right choice for an individual)

I think the concept can be applied pretty broadly. Some more ideas:

  • when learning about a new field, in general, go for textbooks rather than papers 
  • if you use spaced repetition, regularly ask yourself whether the cards you are studying have passed their shelf life --> this can help reduce frustration/annoyance/boredom when reviewing cards
  • some skills have extremely long shelf-life and they seem to overlap with those that compound:
    • learning basic life admin skills
    • learning how to take care of your mental health (e.g. CBT methods)
    • learning how to learn
    • basic social skills

I'm sure there is much more here.

I like this as a concept handle, and as a neat way to distinguish between factual statements that are (pointless, ephemeral) trivia vs. which ones aren't.

This is a really handy formalisation of this. One thing did stand out to me - I'm curious about your rationale for watching out for new media platforms? 

Good spotting. New media platforms aren't like the others on my list. My checklist contains sudden disruptive events. Disruptive events don't have to be bad. Disruptive events can be catastrophic, but they can be neutral or good too. A cure for aging would be on the list if I thought it was likely to happen in my lifetime.

Building an online audience is source of leverage. New media platforms are important to respond to quickly because it is easier to build an audience by being first on a new platform that is growing fast than by fighting for market share on a mature platform.

[I]t could be a good trick to look for waves and ask how one could benefit from them. The prices of gene sequencing and 3D printing are both experiencing Moore's Law-like declines. What new things will we be able to do in the new world we'll have in a few years? What are we unconsciously ruling out as impossible that will soon be possible?

How to Get Startup Ideas by Paul Graham

Oooh, great response! I was hoping for something like this - a good reason to get involved with something I didn't initially see the utility of. 

It also seems related to Elizabeth's article on internet literacy atrophy, which I happened to stumble on today - so there's another reason too. 

Thanks again!

What is considered the half-life of facts now?