Factor Analysis and Realism
In statistics, the idea behind doing a factor analysis (FA) is that there are latent variables, or factors, which are unobservables that explain the observed variables from some data set. For example, if you gave school children a bunch of assessment tests, then you end up with a bunch of data for each assessment (variable). But what you want to know is what factors explain the resulting data. The factors could be income, IQ, parental involvement, classroom size, working memory, teaching approach, etc.
If you can reduce the observed variables (assessments in the example above) to several factors that can be used to reproduce the data, and then show which variables are associated with which factors, you have demonstrated there are indeed latent (unobserved) variables responsible for the data. Of course what the latent variables actually are is a matter of theory, and thus factor analysis can be confirmatory as well as exploratory.
The philosophical question is whether FA demonstrates that realism (of whatever sort) is the case. Why would factor analysis work unless there really are unobservables explaining the results of observations? Is there another way of explaining how the statistics works out?
If you can reduce the observed variables (assessments in the example above) to several factors that can be used to reproduce the data, and then show which variables are associated with which factors, you have demonstrated there are indeed latent (unobserved) variables responsible for the data. Of course what the latent variables actually are is a matter of theory, and thus factor analysis can be confirmatory as well as exploratory.
The philosophical question is whether FA demonstrates that realism (of whatever sort) is the case. Why would factor analysis work unless there really are unobservables explaining the results of observations? Is there another way of explaining how the statistics works out?
Comments (32)
There are 'real possibilities'. Like, if you wanted to model some process, you could factor in variables that you know might effect the outcome, and run the simulation. 'Real possibilities' might be heat, pressure, and so on. Other things, like pixie dust or psychic forces, wouldn't need to be considered because they're not in 'the realm of possibility'.
The question is why there would be an actuality. Why would working memory or any latent variable exist, if the anti-realist view is the correct one?
So if we want to explain why kids succeed or fail in school, and we measure a bunch of things, then we want to be able to reduce our data to what explains success in school. And then we can act on that (assuming an ideal world absent politics).
Now, on a possible anti-realist view of things, if there are no hidden factors, then some kids succeed and some fail, and there are a bunch of observations we can make. But there is nothing beyond that explaining the success and failure. Nothing beyond what we measure. This is in direct contradiction to what factor analysis assumes to be the case. There are things we cannot measure, so we have to resort to a statistical analysis to tease them out.
Like 'instrumentalism' in physics?
IN any case, to answer your question in the OP, I think factor analysis does try and identify 'real causes' on the basis of trends, so I presume it would generally favour a realist attitude.
I forget who said this but some phenomenologist wrote this idea that when one sees an object, although in terms of visual perception all one sees is a surface facing oneself, in a more mental sense one builds the three dimensionality of the object within ones mind by imagining the object as being seen from all directions, a gods eye view.
I don't think an antirealist would just outright deny the existence of unobserved variables, he'd just analyse the way in which they exist as being experiential.
The easiest objection to this is the following: Why couldn't idealism posit ideas that aren't explicit/made manifest?
Or are you simply asking whether there "really are" unobservables? (That would be different than saying that it supports realism in a philosophical sense--realism in the philosophical sense refers to mind-independent existents. What I'm noting above is that the unobservables could be mind-dependent instead (to an idealist, at least))
Re asking simply whether there really are unobservables, regardless of whether they're mind-indepedent or not, I don't see why one couldn't claim that there are not, and that factor analysis is simply an instrumental means of dealing with manifest data that are otherwise difficult to explain in some systematic way, where the instrumental account posits fictions in this case.
Exactly.
Latent variables are inferred, a mental construct, part of a mental model. Thus, consistent with an anti-realist metaphysics.
You have not specified any factor analysis, nor even indicated what sets of observed values should be used in the factor analysis, let alone performed one, so I can't see that there is, so far at least, any philosophical issue to discuss.
Also, you seem to be using an unusual meaning for 'unobservables'. My understanding of the role of unobservables is that they are well-understood concepts that cannot be directly quantified, and for which proxies are used. For example IQ test results are used as a proxy for intelligence, or life expectancy may be used as a proxy for quality of life.
What would you call phenomena that we're not even aware of, so that there's no concept of it, etc.?
(Maybe you're implying that you're an idealist and not a realist? I don't recall your view there, although I suppose I should assume that you're an idealist, because realists seem to be by far in the minority on this board.)
Well, assuming that there are such things, I'd assume they'd be called "unobserved and unconceived phenomena".
Why add "unconceived" to the mix? If it's not observed, then it's an unobservable, period. We might conceive of it, but for one reason or another, we don't observe it. They are two entirely different things.
Perhaps often this is the case, but there is exploratory factor analysis, where you might not know which concepts play the role of the factors. You can take any data set with related variables and do an exploratory factor analysis on it.
Yes, in the model of doing factor analysis. But the fact that it works suggest something more. You can't use the mental construct, as I mentioned above, to explain why the model works on real data.
IOW, this isn't just a mathematical concept. It's use to get at unobserved factors in real data. That's the reason statisticians came up with it. The theory being that there really are such things explaining the data.
That's stated as the motivation for the people who invented factor analysis.
I'm just learning how to use it. You can do a search for factor analysis studies. There's plenty of scientific results and papers.
In this story, scientists have gathered their data on the Solarian ocean. However:
If anti-realism were the case, I would expect that factor analysis would never get farther than what the scientists in Lem's story have gotten with the alien ocean. Scientists and statisticians collect a bunch of data on a wide variety of phenomena which they classify accordingly, but no hidden factors can be inferred to make sense of it.
You understand the distinction between that and realism ("Are they real?") in the "mind-independent" philosophical sense, though, right?
Those are two different questions.
You could see the issue in three stages of questions about whether they're "real:"
(1) We can treat them simply as instrumental utilities where it doesn't matter if they're real in any sense beyond being useful for the theories in question (and one might say that's "real enough"),
(2) Whether they're real in the colloquial sense of "whether they occur" versus just being useful fictions, but where no particular ontological commitment is required regarding just what sorts of occurrent things they are, and where thus the whole range of possibilities is available, and
(3) Whether they're real in the sense of mind-independent things, where to answer that positively, we are making an ontological commitment (at least in one aspect) to what sorts of things they are.
Except for when it comes to school funding or medical treatments. Then you might want to know whether they are just instrumental utilities or actually real.
Well, yeah, depending on the specific example and context, you might want to not just settle on stage (1) or (2) of that. I'm just noting that the question of whether unobservables are real can be taken and answered in different ways.
Yes, especially in theoretical physics.
Yeah, it's most common there to just stop at (A) . . . which is something I brought up just today in the recent MWI thread. Most physicists (as well as mathematicians for that matter) don't care much, in most contexts, about any ontological commitments. They're just looking for instrumental theories that work well. That's the gauge of truth for them.
Seems to me that if you can't demonstrate, either logically or empirically, that the unobserved factors are real things rather than ideas of things, then they are just as consistent with an anti-realist as with a realist stance.
There's a difference between being unobserved and being unobservable.
Quoting Marchesk
Because Terrapin asked "what would you call phenomena that we're not even aware of, so that there's no concept of it[?]"
Quoting Marchesk
A thing can be unobserved but observable, so this is false. That we don't see it is not that it can't be seen.
There can be, sure. "Unobservable" is sometimes used to denote that something is unobservable in principle. But it's also often used to simply denote what we could call "unobserveds," where it was a contingent matter that they weren't observed on that occasion.
To get a fix on that we can turn to that famous non-idealist philosopher Donald Rumsfeld (I'm deliberately misusing the word 'idealist' here, but why not, it's a Thursday after all):
Those phenomena are the 'unknown unknowns'. By contrast I think that the unobservables referred to in the OP are, in Rumsfeldian terms, the 'known unknowns'.