If it's the property you need, and you can't prove it, it's still the property you need - you can't simply define it away. As I said, though, you'll almost alw

If it's the property you need, and you can't prove it, it's still the property you need - you can't simply define it away. As I said, though, you'll almost always be hitting practical limits long before theoretical ones. And as I also said, there's still quite a few useful things we can speak meaningfully about, even in a quite impoverished setting.