What's wrong with Object-Oriented Programming and Functional Programming

I doesn't happen with undergrads only (but that doesn't make the whole profession guilty of it all the time).

> They think you can dismiss a huge paradigm with a glib one-liner: "functions are not objects".

I don't think the article dismisses any paradigm whatsoever. It dismisses the entrenchment in one paradigm at the expense of any other. That's the main point. The explanation given is perhaps a little bit careless, I can concede it.

> Think about it a little bit and you'll see why they are actually very related.

Relation does not imply causation, which I perceived in your wording, but I might have been mistaken. Was I?

> His statement about Java is meant to imply that proper higher order functions and OOP are in opposition in some way

I don't think he meant that, but rather that the way Java never included functions as "primitive types" was a mistake because of that need of OO purity. The Runnable interface (or any interface containing a single method) is an example of that problem (there are other reasons which may support the existence of that interface though).

> I am saying that proper higher order functions alone are enough for a very pure form of OOP, so there is clearly no opposition.

That's debatable. I totally agree with you on the idea that FP let you implement OO. Likewise, OO let you implement closures easily (there's a duality there obviously, as in algebra vs coalgebra). However, I think that OOP (or FP) as a full fledged paradigm included in any language - and not just a library built on top of closures (or closures on top of objects) - makes a lot of sense: it let the language incorporate syntactic sugar for all the specific constructs related to OO, and it also enable the compiler to perform better code analysis (though I suspect that it should be possible with a library based implementation, but that would imply either the compiler to know about it, or it having a very flexible - plugin like - mechanism to include enhancements as libraries as well). I don't think that the latest evolution in Java to include FP is a coincidence. Many languages have already been mixing these paradigms with good success.

> I'm going to ignore the digs at me [...]

Good. Let's get that out of the way. I'm glad we're having a saner discussion.

> If he can't make a simple argument correctly, how am I supposed to have faith that his research isn't similarly full of errors?

I understand your point better now. Initially, I was very afraid you'd be having the very same issue.

I'm not sure I'd agree with respect to programming languages, however. These are artificial languages designed to convey a limited set of ideas, with varying degrees of abstractions over various concepts in electrical engineering and mathematics. Given this, the purpose of a programming language isn't just to communicate with others, it's also to shape how you approach problems.

Anecdotally, learning the strict functional programming paradigm is what allowed me to pass an extremely difficult technical interview recently. The emphasis on dataflow and "do what I mean, not what I say" truly changed how I thought and approached problems. Previously, my years of experience in imperative languages lead me down a road that was a bit too missing-the-forest-for-the-trees when it came time to solve a difficult, interview-style algorithmic question.

I see this happen all the time, with myself and with others, and I think it's a common thing in mathematics (the author is in CS, so he might not get exposed to this as much as I do). I've seen undergrads finally realize that calculus makes sense and explain how much deeper their understanding is now that they've really thought about it, and I smile and nod my head. I've myself touted my own deep understanding like it's not completely trivial to somebody with years of experience.

I think this article shares that sentiment. The author has thought of on his own accord what we all consider a dead and beaten horse, and is shouting his thoughts from his proverbial mountaintop: no paradigm is perfect for every situation.

Best of luck to him for all his thoughts, but he'd better learn when and where to curb his enthusiasm if he wants others to take him seriously. For the record, this doesn't apply to his personal blog. I expect sooner or later he'll have a post talking about how Haskell's pure style is all about giving the sculpter more clay.