[betty boop]

Doesn't that lead to a conclusion that nothing exists unless and until it's been observed?

Not necessarily. This is the old "If a tree falls in the forest and no one is there to observe it, does the tree make a sound?" problem.

Two great friends — Einstein and Bohr — are on record as having quibbled over this problem.

Einstein twitted Bohr in so many words: "Niels would deny that the moon rises in the sky, unless he could see it for himself."

That is to say, the "existence of the moon" depends on Niels having observed the moon. That is, the moon is ontologically dependent on Niels' observation of it, which is an epistemological exercise.

Of course, Bohr denied all this. His answer was that the moon's existence did not depend on his observation of it; He doesn't "create" anything by "seeing" it. Rather, he acknowledges that any description that he could give of the moon surely did depend on his observation of the moon.

Vive la différence!

[tacticalogic]

So what will knowing exactly what “life” is tell you about everything that is not alive?

[Heartlander]

[Bohr] acknowledges that any description that he could give of the moon surely did depend on his observation of the moon.

‘There is no quantum world. There is only an abstract quantum physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about nature…’

‘…We must be clear that when it comes to atoms, language can be used only as in poetry. The poet, too, is not nearly so concerned with describing facts as with creating images and establishing mental connections.’
- Niels Bohr