What do Phal "white roots" mean?

I'm having a hard time accepting the upside-down (right-side down) thing, too, but after seeing so many pictures of greenhouses and other growers doing that, i'm moving towards it, leaning them out and sideways and getting them out of pots and into breezier baskets or pots with more holes.

I just have one question: if the roots start to go limp and "empty", must they be cut off immediately? I have left them on if they were just halfway up and some plants have eventually grown new roots. They seem to last a long time in this poor-root-twilight zone so I was never sure I should really chop every last bit off.

I don't know that it would be absolutely necessary to trim limp roots off right away. I'm not sure how much good they are doing the plant by the time they are soft and limp. Probably not a whole lot. Since the odds are the soft roots will just get mushier, I would remove them.