Sounds extremely interesting! I see numerous references to papers and articles on line, but that I have no access to. What little I did see seems to imply there is no such independent thing as knowledge, which I understand as allowing the paraphrase, no knower, no knowledge. It appears to matter in education. I join you in hoping someone can and will add some light, here.

I must apologize for submitting this question twice: to "general philosophy" as well as to "metaphysics & epistemology". Thank you.

You should probably tell us a bit more of where you are coming from with this query: where have you heard about "constructivism" and "anti-realism" respectively, what specifically have you read? "Vague" is right in the sense that there isn't a single accepted meaning for either term, and at least with respect to anti-realism, it is debatable whether it can even be nailed down to any coherent philosophical position. In the introduction to the SEP article on Moral Anti-Realism Richard Joyce includes this quip from Crispin Wright (which I like to cite, because it applies to so many topics): "[A] philosopher who asserts that she is a realist about theoretical science, for example, or ethics, has probably, for most philosophical audiences, accomplished little more than to clear her throat."

If you do a search for "constructivism," the most prominent results are from the fields of education and sociology (e.g. Review of constructivism and social constructivism), which is probably not quite what you had in mind.

A different kind of constructivism is Constructivism in Metaethics. If that is what you are asking about, then one obvious distinction between constructivism and anti-realism is that the latter refers to a much broader family of views than just metaethics (although seeing as you eventually settled on this forum, rather than Ethics, I am not so sure).

If you did have metaethics in mind, then from the SEP articles (Moral Anti-Realism and Constructivism in Metaethics) we can conclude that it is not even clear whether constructivism belongs to realism or anti-realism (but that may be seen as further evidence that the latter terms are not well-defined). At the very least, following the broad classification of the varieties of moral anti-realism from the first article, we can say that constructivism does not fall under either moral noncognivitism or the error theory.

So here's my (uneducated) crack at answering your question.

According to Michael Dummett, realism about any topic is a commitment to bivalence logic, where the truth value of any statement in that domain transcends the evidence, whereas antirealism is verificationist. The realist believes statements are determinant (either true or false), whereas the antirealist does not absent some means of verifying those statements.

Constructivists argue our knowledge of a domain is constructed by the community responsible for that domain, as opposed to our knowledge coming from the world itself. Therefore, constructivism tends to fall on the antirealism side of things, since the truth of a statement has to be constructed, otherwise it can't be determinant.

Dummett points out that a philosopher can be a realist on one topic, and an antirealist about another. Most philosophers are not one or the other across the board. They pick and choose what to be realist about based on the logic they use for that domain. Which probably means they endorse constructivist views for some forms of knowledge, but not others.

For example, it's perfectly reasonable to be a metaphysical and scientific realist, but think that math and morality are socially constructed. I'd guess quite a few analytic philosophers would qualify.

Thanks for this. What's the reference for Dummett?

My own takeaway so far is in alignment with that Crispin Wright quip: "realism about any topic" is kind of an oxymoron, since it means different things to different people in different contexts, and I am skeptical as to whether it means anything at all as a general concept. But more specific positions might be more robust.

There are three kinds of midwife. The realist announces the baby's sex according to what it is. The anti-realist announces the sex the way she sees it. The constructivist makes its sex what it is by her announcement of it. [Apologies to Sidney Morgenbesser, Judith Butler and a whole lot of others.]

https://iep.utm.edu/dummett/#H3

In the general, I take realist to mean the domain in question exists independent of humanity. Man is not the measure for things that are real, because they don't depend on us to exist. I think you would agree that the universe qualifies for being real, and that only solipsists seriously doubt that, although other positions would argue over what the world is, whether science provides us a somewhat accurate account, and to what extent we can know.

Yes, I think that its necessary that I give you some background about the origin of this question. Quite a number of years back I did courses in Religious Studies. One of the compulsory papers was "Mysticism and Religion". Fairly recently I decided that a reread of some of the text books used in these courses could be of some value to me. It started with reading "Mysticism, Mind and Consciousness" by Robert Forman. In this book Forman takes an anti-constructivistic position in regard to so-called "mystical experiences - events experienced by people belonging to the different religions of the world. Forman's opponents, including people like Wainwright, Smart, Hick, Penelhum, Gill, Proudfoot and especially Steven Katz is viewed by Forman as "constructivists". Forman defines "constructivism" as follows: "Constructivism is the view that in significant ways the mystic's conceptual and linguistic scheme determines, shapes, and/or constructs his or her mystical experiences". I think that it is clear from this definition that "constructivism" refers to experiences which are all in some way or another mind dependent. Opposed to this view is Forman's defence of his own anti-constructivistic position. I think that
the closest that Forman comes to explaining this position, is by his reference to "pure conscious events". This, according to him, happens when consciousness becomes aware of itself, it is becoming conscious of being conscious.
However, please bear in mind that the above is just to give you some background and not to argue for or against Forman's position - enough has already been written on this topic. After having read the book, my thoughts returned to "constructivism" and the possibility of applying this concept to other fields of philosophy, especially epistemology and also to some extend to metaphysics, instead of limiting its usage to mysticism. Thinking about knowledge, how, why and what we know, took me back to the old controversy between empiricism and rationalism and how Kant reconciled these two positions with his transcendental idealism. What Kant is saying is that we can know phenomena by means of perception and reason although we cannot know phenomena as they are in themselves. In other words, our minds plays a part / is involved in our knowledge of phenomena and is this way "constructivistic" in obtaining knowledge of the phenomena that we know. So far, so good?
My mind goes along avenues and arrives at the realism / anti-realism distinction. I open my "Oxford Companion to Philosophy" and read Timothy Williamson's article on this topic. The most important point which I think Williamson is making, is his view that both "realism" and "anti-realism" are not positions, but directions: The more mind-dependent a thing becomes for it to exist, the more anti-realistic it becomes. Let's take the contents of our dreams when we are sleeping as an example of moving quite strongly in an anti-realistic direction, Looking with others at a concrete object like a tree and agreeing that it exists to some extend independently of our minds is an example of moving in a realistic direction.
Perhaps I've succeeded with this explanation to make it clear why I have a problem with the nature of the relationship between "constructivism" and "anti-realism" Your views/comments to make this clearer to me will be appreciated.

I've been struggling for last month or so so to distinguish between the concepts of "constructivism" and "anti-realism". — Daniel C

I wonder if you've answered your own question in that they're the obverse and reverse of the same coin. Or, by their names, one active, the other reactive.

But the preliminary question, it seems to me, concerns knowledge itself. And it seems obvious that nothing is known, nor can be known, unless it is known. Knowledge, then, presupposes a knower who knows. And that just leads back to Kant, whos ideas you appear to grasp fairly well.

The (a) trick with Kant is to keep in mind the distinction between pure and practical. Thus what particular knowledge is depends on how it is being used. And children get this right while some philosophers seem to get tied up in knots with it. And in parallel, teachers, usually, get this right while some "educators" get tied up in knots about it.

Now then. What, exactly, is your problem?

In the general, I take realist to mean the domain in question exists independent of humanity. Man is not the measure for things that are real, because they don't depend on us to exist. I think you would agree that the universe qualifies for being real, and that only solipsists seriously doubt that, although other positions would argue over what the world is, whether science provides us a somewhat accurate account, and to what extent we can know. — Marchesk

This sounds reasonable, but close scrutiny erodes the sense of understanding. What sort of independence are we talking about? A world without humanity wouldn't be the would in which we live, so the actual world depends on humanity at least in this sense. Is it mind-independence that we are after? That too is a slippery idea.

Concretizing the question may help: instead of asking about realism and anti-realism in general, consider some specific issue where controversy is more apparent.

This goes for your question as well, I think. Your point of departure were some writings on religious mysticism, which give the notion of "constructivism" a particular shape (I'll take your word for this). From there you decided to generalize that notion, but in the process of generalizing it lost most of its particulars and morphed into some vague notion of "anti-realism." That is to be expected.

Earlier I pointed you to another, somewhat more concrete example where several varieties of anti-realism are purported to be distinguished, and one of these varieties is also referred to as "constructivism" - which makes it at least notionally distinct from the broader concept. But generalizing from that example would probably run into the same issue, since not all subspecies would survive the process. What would be the generalized version of the error theory, for example?

A world without humanity would be somewhat like the kind of world we live in because the world was already here when we subsequently arrived to live in it.

A world without humanity would be somewhat like the kind of world we live in because the world was already here when we subsequently arrived to live in it. — Cuthbert

A world that was isn't the world that is though. Or if it be the same world, then it is the world with humanity in it.

Possibly. When we've all gone I'll let you know. Oh, hang on....

A world that was isn't the world that is though. Or if it be the same world, then it is the world with humanity in it. — SophistiCat

Yeah, but the realist argument is that the world goes on existing without humanity in it. As opposed to the world merely being a kind of appearance to human minds. All those stars and planets out there, the course of most of evolution on this planet (prior to and after us), and everything that goes on beyond our perceptual abilities on the small or large scale does not depend on us knowing about it. Only the things we humans influence, like cultural artifacts or domestication.

Human languages like English clearly depend on humans for existence, whereas Pluto does not, on a realist account, even if we change our minds on its status as a planet. When we ask whether mathematical objects exist (or at least some branches of math), we're asking whether it's more like English or like Pluto. If the universe has a mathematical structure, then that structure exists independent of human minds, unless it's just an appearance.

But yes, the details of realism/anti-realism debate depends on the domain. Moral values wouldn't be real in the same way that matter/energy is, whatever they would be. But they would have to exist as something more than a human construction, unlike money or Harry Potter.

Yeah, but we only occupy a small part of one solar system as one species out of many. Independence means our existence isn't necessary for the rest to exist. That's quite different from cultural artifacts or human language, which clearly depend on us for existence. — Marchesk

So we need to explore what we mean by dependence (and the significance of any such dependence). The Anthropic Principle is one example where the usual direction of dependence is reversed: the world is/must be such as to accommodate the existence of humanity. The most far-reaching interpretation of this principle is explanatory. Why is the world such as it is? In part because our existence, which we take as given, puts various constraints on how the world could be.

the world is/must be such as to accommodate the existence of humanity. — SophistiCat

As opposed to jelly fish or neutron stars? Humans aren't special in that. Anything in the universe exists because things are a certain way and not some other. Dependence in the realism debate means dependence on human perception, language, cognition, culture. Take a historical event. History is a reconstruction of what historians think happened based on their interpretation of available evidence.

One might be tempted to suppose that reconstruction is all there is, as opposed to there having been a real event in the past the evidence is based on. If historians had a time machine, they could travel there. But if it's merely a reconstruction, then there was no real event in the past. It's just human activity creating accounts of the world as it appears to us (the evidence is an appearance of the empirical world). We're telling ourselves stories. There used to be several posters on here who defended that sort of subjective idealist view.

I guess in the case of history, constructionism is a necessary aspect, but most historians are realists about the past. So constructionism need not be anti-realist.

Thank you for all your contributions in attempting to find greater clarity on this issue, It feels, however, if we are still only busy to encircle the problem - and I, myself, being in one of those circles.
I've considered everything said thus far and want at this point to propose another approach. I must immediately mention that you might find me guilty of trying to oversimplify things and it might be true, but it has always been my view that professional philosophers tend to make issues too complex, thereby alienating many people from this subject. My objective has always been to try and make philosophy as accessible as possible to as many people as possible, but thereby not denying that there are issues in this subject which are really complex.
(a) The realism / anti-realism distinction: this should be viewed as a distinction belonging to metaphysics, and more specifically to ontology: the emphasis here is after all on the "existence" of things. Therefore, the more mind-dependent a thing becomes for it to exist, the more anti-realistic it becomes for it to retain its existence status. Moving in the opposite direction things are becoming more realistic as far as their existence status is concerned.
(b) The constructivism / anti-constructivism distinction: this is more of an epistemological type of distinction: the emphasis is here on a-priory knowledge of the knower of a subject / experience and how much this a-priory knowledge influences his view / understanding of the subject / experience. Therefore, the greater the impact of his a-priory knowledge, the more constructivistic his view / understanding becomes. The opposite situation in this case will lead to knowledge which will be more anti-constructivistic.
What do you think? How far can we get with this one? Can it be, perhaps to some extend if then not fully, or is it doomed to sink as a whole? One thing that bothers me here is: am I not busy here trying to make out a case for metaphysics being dependent on epistemology?

One thing that bothers me here is: am I not busy here trying to make out a case for metaphysics being dependent on epistemology? — Daniel C

That sounds antirealist!

In politics, constructivism is opposed to realism in this way:

A political realist talks about influence (like the influence of the US on the rest of the world) as if it's a component of a machine, as if influence is something the US possesses and can direct at will.

A constructivist says this is a reification that causes confusion. American influence is all over the place in tiny bits, like a Coca Cola here, some American music there.

The constructivist says the US doesn't own it and controls it in a limited way.

Modernist versions of constructivism believe that there is a real world that we only have indirect access to via our constructions of it. Postmodern constructivism, also known as radical constructivism( see Maturana, Von Glasersfeld, and Varela) believe that our constructions of the world don’t represent a reality supposedly existing independently of us , but enact a world partly determined by our constructions.