Enforcing Type Distinction

post by lionhearted · 2020-07-31T11:39:20.026Z · score: 27 (11 votes) · LW · GW · 1 comments

The phrase "Enforcing Type Distinction" was mentioned and fleshed out here 12 years ago, but only appeared exactly once and that exact phrasing didn't catch on.

I think "Enforcing Type Distinction" has value as a concept (to think more clearly), as a phrase (to discuss the thing), and potentially as a community norm (something we could all agree should happen more often, analyze when and where it does not happen in general discourse, and politely encourage each other be more mindful of).

For context, I got there by re-reading Trying to Try [LW · GW]: 

The first elementary technique of epistemology—it's not deep, but it's cheap—is to distinguish the quotation from the referent [? · GW].  Talking about snow is not the same as talking about "snow".  When I use the word "snow", without quotes, I mean to talk about snow; and when I use the word ""snow"", with quotes, I mean to talk about the word "snow". 

Which led to The Quotation is not the Referent [LW · GW]:

The problem, in my view, stems from the failure to enforce the type distinction between beliefs and things. [...] It is immensely helpful, when one is first learning physics, to learn to keep track of one's units—it may seem like a bother to keep writing down 'cm' and 'kg' and so on, until you notice that (a) your answer seems to be the wrong order of magnitude and (b) it is expressed in seconds per square gram. Similarly, beliefs are different things than planets.  If we're talking about human beliefs, at least, then:  Beliefs live in brains, planets live in space.  Beliefs weigh a few micrograms, planets weigh a lot more.  Planets are larger than beliefs... but you get the idea.

After reading those two posts, you get to a familiar concept — words aren't things; a lot of confusion are about words and not things, etc. 

Also discussed in Disputing Definitions [LW · GW]: 

"If a tree falls in the forest, does it make a sound?"

[...]

""Do you think that 'sound' should be defined to require both acoustic vibrations (pressure waves in air) and also auditory experiences (someone to listen to the sound), or should 'sound' be defined as meaning only acoustic vibrations, or only auditory experience?"

Tom Bretton's comment on TQINTR [LW(p) · GW(p)], from 12 years ago, seems like it's worth another look:

The problem is that identity has been treated as if it were absolute, as if when two things are identical in one system, they are identical for all purposes.

That seems correct, but this whole class of error seems rather sneaky.

Take a somewhat related point — a man might measure 170 centimeters tall in both Oslo and Manila, but he might be "short" in one place and "tall" in another. Thus, very counterintuitively, "short"/"tall" and measured height in centimeters are actually different types

One is a mathematical measurement; the other is a classification relative to what is normal or expected within a given group, society, or profession.

(A "short" professional basketball player might be in the 99th percentile of measured height of all people alive.)

This concept gets talked around and analyzed here plenty of different ways, but "enforcing type distinction" might be a useful phrase to add to both one's mental and verbal toolboxes.

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comment by Dagon · 2020-07-31T20:55:20.842Z · score: 12 (3 votes) · LW(p) · GW(p)

Related to https://en.wikipedia.org/wiki/Dimensional_analysis in physical sciences. One of the first questions to ask when comparisons or equivalence (I tend to avoid "identity" as a term - "equivalence" is more flexible and brings less baggage) are asserted is "what are the units for that?"

The example of height is a good one - the units can be length or percentile of a given distribution, and once you recognize those units, the ambiguity is removed.