> that does not have a technical meaning

I don't think the definition is very refined, but I think we should be careful to differentiate that from useless or meaningless. I would say most definitions are accurate, but not precise.

It's a hard problem, but we are making progress on it. We will probably get there, but it's going to end up being very nuanced and already it is important to recognize that the word means different things in vernacular and in even differing research domains. Words are overloaded and I think we need to recognize this divergence and that we are gravely miscommunicating by assuming the definitions are obvious. I'm not sure why we don't do more to work together on this. In our field we seem to think we got it all covered and don't need others. I don't get that.

  > In this view, if a machine performs a task as well as a human, it understands it exactly as much as a human.

And I do not think this is accurate at all. I would not say my calculator understands math despite it being able to do it better than me. I can say the same thing about a lot of different things which we don't attribute intelligence to. I'm sorry, but the logic doesn't hold.

Okay, you might take an out by saying the calculator can't do abstract math like I can, right? Well we're going to run into that same problem. You can't test your way out of it. We've known this in hard sciences like physics for centuries. It's why physicists do much more than just experiments.

There's the classic story of Freeman Dyson speaking to Fermi, which is why so many know about the 4 parameter elephant[0], but it is also just repeated through our history of physics. Guess what? Dyson's experiments worked. They fit the model. They were accurate and made accurate predictions! Yet they were not correct. People didn't reject Galileo just because the church, there were serious problems with his work too. Geocentricism made accurate predictions, including ones that Galileo's version of Heliocentrism couldn't. These historical misunderstandings are quite common, including things like how the average person understands things like Schrodinger's Cat. The cat isn't in a parallel universe of both dead and alive lol. It's just that we, outside the box can't determine which. Oh, no, information is lossy, there's injective functions, the universe could then still be deterministic yet we wouldn't be able to determine that (and my name comes into play).

So idk, it seems like you're just oversimplifying as a means to sidestep the hard problem[1]. The lack of a good technical definition of understanding should tell us we need to determine one. It's obviously a hard thing to do since, well... we don't have one and people have been trying to solve it for thousands of years lol.

  > Just my opinion, but my professional opinion from thirty-plus years in AI.

Maybe I don't have as many years as you, but I do have a PhD in CS (thesis on neural networks) and a degree in physics. I think it certainly qualifies as a professional opinion. But at the end of the day it isn't our pedigree that makes us right or wrong.

[0] https://www.youtube.com/watch?v=hV41QEKiMlM

[1] I'm perfectly fine tabling a hard problem and focusing on what's more approachable right now, but that's a different thing. We may follow a similar trajectory but I'm not going to say the path we didn't take is just an illusion. I'm not going to discourage others from trying to navigate it either. I'm just prioritizing. If they prove you right, then that's a nice feather in your hat, but I doubt it since people have tried that definition from the get go.