What the frick are units? Why do we need them to make measurements? Do they bridge the gap between the abstract and the concrete? They're arbitrary too but somehow still work. Wtf why?

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Groups of amounts which can be related

If different things need to be related, does that imply distinct things really exist?

According to SI there are 7 distinct things from which all other measurements are derived.

yes, although depending on who you ask, some think the fundamental dimensions should be different.

i've heard some pretty convincing arguments that 'mass' should be replaced with 'force', for example.

>i've heard some pretty convincing arguments that 'mass' should be replaced with 'force', for example.

But mass is already a component of force

NTA but If you decide force (N) is the standard unit, all that changes is Force is then described a component of mass and the kg is redefined as a N•s^2/m. I don't think this has any real effect on physics. And while I don't know the arguments for why some think SI should be defined using force over mass, I will say all things with mass are able to exert force between objects (to my knowledge), but mass is not a requirement for something to exert a force (photons), so I don't think it's far fetched to believe the Newton is a more accurate basis.

Or force is a component of mass, if you look at it the other way. From the experimentalist point of view - force is the meaningful measurable quantity, and mass is the derived quantity (even though the theorist would argue mass is the more intrinsic property).

Well mass is just apparent force applied over some area, no?

No

>7 distinct things

How does spacetime factor into this?

Why would a mathematical model factor into units of measurements?

Units are constants. 2m + 3m = 5m. What the frick is an m? Who cares, there's 5 of them.

Units can convey relative as well as absolute quantity. Fractions, angles, etc.

A meter is defined as 1/10,000,000 the distance between the north pole and the equator. If you want to define it using a universal constant it would be 1/299,792,458 the distance light travels in a vacuum every second. If I say the distance from where I am to New York is 5, I'm not conveying anything. Five what? km?, M? mm? Mpc? I haven't defined anything with a base unit, if instead I say I'm 5km and thus 5 (1/10,000 the distance from the north pole to equator) away from new york, where (1/10,000 the distance from the north pole to equator) = 1km I have actually defined an empirical measurement.

>Do they bridge the gap between the abstract and the concrete?

Not really. Dimensional analysis usually works not by looking at the units necessarily, but what the units convey. Meters convey distance, seconds convey time, joules convey energy, ect. The usefulness lies in how we manipulate the "dimensions" of the physical system.

To distinguish between different measurable quantities.

Your friend walks up to you and says "give me twenty". Does he want twenty dollars? Twenty kilograms of uranium? Twenty minutes of your time?

That is a slang for fentanyl overdose where fake twenty dollars were involved.

units don't exist, one day we will find that given the right choice of constants everything will be measurable with the same unit

>units don't exist,

Yet your penis is exactly two centimeters long...

>we will find that given the right choice of constants everything will be measurable with the same unit

Well no. That doesn't work out at all which is why it isn't done even though it could be done.

>What the frick are units? Why do we need them to make measurements? Do they bridge the gap between the abstract and the concrete? They're arbitrary too but somehow still work. Wtf why?

Have you ever used a type system in a programming language? Units are a little bit like that. Arguably, they're exactly like that if you formulate an appropriate type system. The consistency of the types is a sanity check. Dimensional analysis is basically making use of the Curry-Howard correspondence to show how your calculations satisfy a theorem about units.

it just werks

This is moronic

Just use kiloseconds if you really want a 10^n time unit

That sounds good in theory but I read a novel once where all times were expressed as power-of-10 multiples of a second and it was fricking incomprehensible.

They're literally just useful ways of grouping quantities, that's all

Units let you quantify both concrete and more abstract things. If I said that my speed is 5, you naturally ask "5 what?". If I said that there's 9 in the electrical system, you would ask "9 what"

>If I said that there's 9 in the electrical system, you would ask "9 what"

heh

They are noticeable changes in the perception of an event, like one sheep then two sheeps, it can be way more arbitrary than that like a fraction of an average speed, those are mostly useless

>the abstract and the concrete

they both are buzzwords