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Comment by 5e92cb50239222b | Hacker News Reader

Yeah, I don't think so. If it's 0°C outside, I know it's probably time to put winter tires on because the water in the puddles will freeze. If water in the pot on my stove is close to 100°C, I know it will boil soon. Same with dates — it has nothing to do with being machine readable or not, dates should go from largest to smallest (yyyy-mm-dd, etc) or vise versa, not turn 180 degrees at midpoint for some reason. Your units make no sense, you're drawing the bullseye afterwards if remember my idioms correctly.

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I am usually an apologist for imperial units thanks to the divisibility by 3 and "human" scale, but temperature is ironically the one that I think is the silliest. It's basically arbitrary.

The original idea of Farenheit was that 0-100 was the range between the freezing point of salt water and human body temperature, and it was designed to be convenient for use in labs. At the time, 0F was the coldest temperature you could reliably make in a lab environment (using a saltwater ice bath). 100F was when the thing started to be uncomfortable to touch, I guess?

Sure, as an American living in the northeast, it is pretty convenient for my current use - temperatures vary from 0 (sometimes below) to a little less than 100 over the year and I know what "jacket weather" is - but that doesn't really mean anything if you don't live in this exact climate. I imagine that if we switched to Celsius tomorrow, after re-learning the numbers for "put on a sweater" and "put on a jacket," it would be about the same.

> 100F was when the thing started to be uncomfortable to touch, I guess?

“Uncomfortable to touch” heavily depends on thermal capacity (how much heat there is in the object to touch) and thermal conductivity (how fast the object can get that heat into your skin), so I would think defining that exact point to be quite the challenge.

As to the Fahrenheit scale, it’s worse. https://en.wikipedia.org/wiki/Fahrenheit:

“The other limit established was his best estimate of the average human body temperature, originally set at 90 °F, then 96 °F (about 2.6 °F less than the modern value due to a later redefinition of the scale)”

So, Fahrenheit arbitrarily picked 100 °F as some distance above the point for average human body temperature, changed it to 96 °F, and the scale was later redefined.

And still people claim that scale is less arbitrary than Celsius, Kelvin, Réaumur, etc.

In what scenario have you checked the temperature of the water on your stove to see how close it is to boiling?

I think of <0F and >100F as being when weather starts becoming lethal if you are poorly prepared.

People can die from "low" temperature as high as 10 C or 50 F.

While we're pointing out extreme outliers out of context to the discussion, water can also remain liquid well below 0c https://en.m.wikipedia.org/wiki/Supercooling

The lethality greatly depends from place to place and that's hardly "extreme outliers". For example Hong Kong's record low temperature is 0.0 °C [1] and a single digit Celcius is considered "very cold"; people can and do die of hypothermia at that range if they are "poorly prepared".

[1] https://en.wikipedia.org/wiki/Hong_Kong#Climate

If your body temp is over 100 F, you have a fever. If the outside is 100 F, it's too damn hot.

The bottom end is much harder to justify but I believe the idea was that you wouldn't have to regularly deal with negative numbers.

But both F and C are completely arbitrary. That's the least messed up part of the non-SI unit system.

Freezing and boiling water really does not seem that arbitrary to me.

What's the pressure for your nonarbitrary boiling point? In SI units please.

It know it's not SI level scientific, but still, it's not as arbitrary as the "temperature of a normal human body".

0°F: cold, 100°F: warm

0°C: cold, 100°C: dead

0 K: dead, 100 K: dead

There is no degree symbol in Kelvin.

Thanks, updated.

300 K: about ideal

< 300 K: cold

> 300 K: hot

Let's switch to Kelvins

> you're drawing the bullseye afterwards if remember my idioms correctly.

That's informally known as the Texas Sharpshooter fallacy

So is the few examples from the OP...

I believe that cratermoon is helpfully reminding 5e92cb50239222b of the name of the formal fallacy 5e92cb50239222b is talking about.

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