It’s a mantra for many scientists, not to mention many business managers, that if you can’t measure it, it’s not real. On the other hand, I’ve been told by a lot of people, mostly non-scientists, and occasionally humanistic scholars including philosophers, that not everything knowable is measurable.
But what exactly is a measurement? My intuitive understanding of the term fits, more or less, with this Wikipedia definition:
There’s a sense that measurement is a precise thing, usually done with standard units, such as kilograms, meters, or currency denominations. But Doug Hubbard argues in an interview with Julia Galef, as well in his book How to Measure Anything, that measurement should be thought of as a reduction in uncertainty. More precisely, he defines measurement as:
A quantitatively expressed reduction of uncertainty based on one or more observations.
Hubbard, Douglas W.. How to Measure Anything: Finding the Value of Intangibles in Business (p. 31). Wiley. Kindle Edition.
The observation part is crucial. Hubbard argues that, for anything we care about, there is a difference between what we’ll observe if that thing happens and what we’ll observe if it doesn’t. Figure out this difference, define it carefully, and you have the basis to measure anything, at least anything knowable in this world. The more the differences can be defined with observable intermediate stages, the more precise the measurement can be.
One caveat: just because it’s possible to measure anything knowable doesn’t mean it’s always practical, that it is cost effective to do so. Hubbard spends a lot of time in the early parts of his book discussing how to figure out the value of information to decide if the costs of measuring something is worth it.
In many cases, precise measurement may not be practical, but not all measurements must be precise in order to be useful. Precision is always a matter of degree since we never get 100% accurate measurements, not even in the most sophisticated scientific experiments. There’s always a margin of error.
Measuring some things may only be practical in a very coarse grained manner, but if it reduces uncertainty, then it’s still a measurement. If we have no idea what’s currently happening with something, then any observations which reduce that uncertainty count as measurements. For example, if we have no idea what the life expectancy is in a certain locale, and we make observations which reduces the range to, say, 65-75 years, we may not have a very precise measurement, but we still have more than what we started with.
Even in scenarios where only one observation is possible, the notorious sample of one, Hubbard points out that the probability of that one sample being representative of the population as a whole is 75%. (This actually matches my intuitive sense of things, and will make me a little more confident next time I talk about extrapolating possible things about extraterrestrial life using only Earth life as a guide.)
So, is Hubbard right? Is everything measurable? Or are there knowable things that can’t be measured?
One example I’ve often heard over the years is love. You can’t measure, supposedly, whether person A loves person B. But using Hubbard’s guidelines, is this true? If A does love B, wouldn’t we expect their behavior toward B to be significantly different than if they didn’t? Wouldn’t we expect A to want to spend a lot of time with B, to do them favors, to take care of them, etc? Wouldn’t that behavior enable us to reduce the uncertainty from 50/50 (completely unknown) to knowing the answer with, say, an 80% probability?
(When probabilities are mentioned in these types of discussions, there’s almost always somebody who says that the probabilities here can’t be scientifically ascertained. This implies that probabilities are objective things. But, while admitting that philosophies on this vary, Hubbard argues that probabilities are from the perspective of an observer. Something that I might only be able to know with a 75% chance of being right, you may be able to know with 90% if you have access to more information than I do.)
Granted, it’s conceivable for A to love B without showing any external signs of it. We can never know for sure what’s in A’s mind. But remember that we’re talking about knowable things. If A loves B and never gives any behavioral indication of it (including discussing it), is their love for B knowable by anybody but A?
Another example that’s often put forward is the value of experience for a typical job. But if experience does add value, people with it should perform better than those without it in some observable manner. If there are quantifiable measurements of how well someone is doing in a job (productivity, sales numbers, etc), the value of their experience should show up somewhere.
But what other examples might there be? Are there ones that actually are impossible to find a conceivable measurement for? Or are we only talking about measurements that are hopelessly impractical? If so, does allowing for very imprecise measurement make it more approachable?