Comment by Mordisquitos | Hacker News Reader

Comment by Mordisquitos | Hacker News Reader

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I have to nitpick Nate Silver on a tangential point here (emphasis mine)

> The more complications you introduce into an analysis, the more confounding variables that you attempt to control for, the more you expand researcher degrees of freedom — in other words, decision points by the analyst about how to run the numbers.

> I don’t think it’s quite right to say these decisions are arbitrary. Ideally they’ll reflect a statistician’s judgment, experience and familiarity with the subject matter.

But, according to the sentence immediately following the one I highlighted, it absolutely is quite right to say those decisions are arbitrary!

They are arbitrary inasmuch as they are arbitrated by the statistician's educated judgement and experience. That these decisions are arbitrary does not intrinsically strip away their value. Rather, it subordinates their value to the presumed ability of their arbiter — in this case the statistician, whom we presuppose is well trained and capable.

I feel that in common parlance the word "arbitrary" is undergoing the opposite process of the term "literally". Where one word is losing its meaning by arbitrarily narrowing it down too much, the other is literally losing its meaning by making it too broad. It figuratively grinds my gears.

I don't think the word "arbitrary" is currently undergoing any change, it hasn't been used the way you use it in like 400+ years.

Wait, so what does arbitrary mean to you if not "the result of a judgement or choice"? Is it just a synonym for random to you?

Yes, that’s what it means for me. I’ve never heard someone use the word arbitrary to mean anything other than “a random choice”, or even “a poorly thought-out choice”.

My professors in grad school explicitly discouraged use of that word anywhere in technical writing, as they felt it would immediately give the reader the impression that the actions taken in the research were not thought through. Example: “This new technique enables arbitrary manipulations of data” should instead be replaced by something like “this technique enables a wide range of manipulations of data”.

I’m not convinced by the argument in your second paragraph. It actually makes it seem like arbitrary means exactly “based on judgment or choice” if it can be replaced so easily with “a wide range of”. How was the “wide range” chosen, if not arbitrarily?

It means something like "any randomly chosen manipulation is possible", or "so many possibilities that I don't feel like listing them, anything you can think of will probably work".

> I’ve never heard someone use the word arbitrary to mean anything other than “a random choice”, or even “a poorly thought-out choice”.

That's shocking, I use it to mean "the result of a judgement or decision" about a dozen times a day, such as "it's not random, it's arbitrary". I had no clue people had an alternative definition for it. I'm even more surprised that otherwise ostensibly-educated people have no clue about the traditional definition.

Can you find any recent dictionary with your definition, or modern printed example of the word used in this way?

Etymonline cites a 1640s dictionary with the present-day definition: https://www.etymonline.com/word/arbitrary

> Can you find any recent dictionary with your definition, or modern printed example of the word used in this way?

sure, https://www.wordnik.com/words/arbitrary: "Based on or subject to individual judgment or preference." is the second definition on the page. You clearly didn't even bother googling.

Regardless, I'd argue that arbitrary as distinct from "random" only has one definition—the one where judgement, choice, or preference is exercised. This is the useful way to use the word, hence my shock. Especially in a technical context where the connotation of petty abuse of judgement makes no sense.

Finally, there are cases where it's indistinguishable from arbitrary. For instance, if you're defining a pure computation on some integer, the distinction between arbitrary and random is meaningless.

Throwing the word away (as I interpret your sentiment to argue for) seems like the worst possible interpretation and just as likely to lead to confusion.

I don't think it means quite the same thing as random.

"The judge is giving out random sentences" means the judge is rolling a die or something, literally randomizing each sentence.

"The judge is giving out arbitrary sentences" means the judge is sentencing based on how they feel in morning, or the opinion of the last person they talked to. The decisions are not random, but they aren't based on any coherent set of rules or logical framework. The judge could have made a different decision and it would have made just as much (or just as little) sense.

Another common usage is calling something an "arbitrary distinction". For example, skyscrapers are often defined as buildings that are at least 100 meters tall. That is an arbitrary distinction, in that there is no significant difference between a 99 meter and 101 meter building. It's obviously not random, it was picked because 100 is a nice round number, but when we say it's arbitrary that means we could have drawn the line at any other number and it would have worked fine. In fact, some people define skyscrapers as being at least 150 meters tall, and there is no logical reason that either of these number are better. They are both arbitrary, and saying that "your 23-story building is a high-rise but my 24-story building is a skyscraper" is making an arbitrary distinction.

So back to Nate Silver's quote:

> I don’t think it’s quite right to say these decisions are arbitrary. Ideally they’ll reflect a statistician’s judgment, experience and familiarity with the subject matter.

If these decisions were arbitrary, that would mean the statistician isn't making educated choices. They're thinking "I just saw a cool article on this regression technique, let me try that", or "my favorite programming language is good at X technique", or "I've been wanting to practice Y technique". When asked why they made a particular decision, the statistician might not have a logical explanation.

If the decisions are not arbitrary, that would mean that other statisticians are likely to agree with the decision, or at least understand the logic behind it.

If I heard someone say that I would think they're making the point only that it was based on personal whim and not pure statistical chance. I wouldn't interpret it to mean that the person's whims are in any way reasonable, just that they're theirs.

The first dictionary result when Googling says:

> arbitrary (adjective)

> based on random choice or personal whim, rather than any reason or system.

> ex: “his mealtimes were entirely arbitrary"

Natural language is imprecise, so there are many definitions, but that fits with how I interpret the word. I wouldn’t think of something like “the well researched opinion of an expert”, which certainly is the result of a judgement, as being “arbitrary”.

For me, arbitrary means something like "not constrained by rules; able to be chosen at will". An arbitrary choice doesn't have to be "random" in the strict sense of being chosen by nondeterminstic chance, although people often use "random" to mean something similar to "arbitrary" in colloquial speech.

It can have good or bad connotations: "Emacs's configurability means you can extend it in arbitrary ways" is good; "Russia is known for arbitrary detention of political dissidents" is bad.

Seconding, here, that I've almost-always heard arbitrary/arbitrarily to mean (slightly differently than the sibling commenter) "able to be chosen freely, without any loss of generality"; though, yes, I have also heard your usage of "by personal judgement, disregarding established rules or convention".

In fact, I just had cause to use the term again, which prompted me to return here to describe my usage a little bit more.

I was documenting a configuration file, and noted that one particular value was chosen "arbitrarily". What I meant by that (and what I am reasonably confident that my audience would understand) is that my choice of that value was not influenced by any other concerns - I did not have to make sure it matched some other value in the file (or in another configuration value), or that it conformed to some enumeration of permitted or significant values.

So - yes, I was technically stating that the value was "the result of a judgement or choice", but _much more strongly_ I was stressing the fact that (personal) judgement was the _only_ factor in the selection, not conformance to other prior values, rules, or restrictions. So - not purely random, but in some sense "closer" to random than to pre-determined.

I agree with you here (https://news.ycombinator.com/item?id=37731820) that entirely throwing away the meaning of the word "arbitrary" and making it a synonym for "random" would not be useful - but I don't think that's what's proposed. Arbitrary is (and, I believe, always has been) a word which stresses the importance of choice and judgement - but sometimes that means "strongly considered judgement was applied here to select the optimal option", and other times it can mean "any selection which you choose is probably satisfactory here - there are no hidden constraints, rules, or requirements".

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