Or, as Terry Pratchett puts it in The Fifth Elephant,
"No one actually saw [the fifth elephant] land, which raised the interesting philosophical point: When millions of tons of angry elephant come screaming through the sky, but there is no one to hear it, does it--philosophically speaking--make a noise?"
Well, if you buy some yarn,
Noro Silk Garden (Ravelry link)
cast on for a project right away, rip it out, cast on again , and then re-rip and no knitter has seen you do this, does the yarn--philosophically speaking--count as an in progress project to make you feel like you are accomplishing something with your knitting?
I mean, I totally gave the yarn a chance to make some awesome mittens and it just wouldn't cooperate with my vision. Now it is de-ball banded and unwound. Is it an unfinished project? Or since I have abandoned that project(s) does it revert to Stash, waiting to be used up?
The issue boils down to what is the exact definition of "on the needles." Is it a mental "on the needles" where I think of how if it won't make mittens maybe it will make a scarf or is it a literal "on the needles" where the Noro is physically cast on. What does it mean if I push the correct needles into the balls so I can grab it on my way out the door and cast on later? Can a project be half-on the needles?
I mean, it's a lot easier to justify a new yarn purchase on a tight budget if I can breezily say "Oh, I've got that Noro on the needles (implying it will be off the needles soon)" instead of "Oh, I've got that Noro in the Stash that needs to be used up."