This quote caught my attention, but I wasn't sure why. So I sat still and thought about it for a few minutes. What was Simone Weil trying to say? Hard to know when I don't know anything about her, so I Googled her name and found out that Weil was an early 20th century philosopher and Christian mystic known for her compassion.
Is she saying that most of our 'real' life is, effectively, in our heads? It is what we imagine or it is the stories we tell ourselves that create the world we see and experience? That was my initial interpretation of the sentence. Every individual processes the world through self-created filters - which is why witnesses to an accident or crime will all report seeing different things, even though they watched the same event - and most of these filters are created from ideas that are linked in ways that only the individual will see. It is real to him or her, but it would very likely be fiction or "an active imagination" if described to somebody else.
But I'm always very nervous and cagey about trying to understand the profound statements of philosophers, because I always feel that I'm getting it wrong. Maybe she means something completely different! Maybe Weil's simply saying that life can only be real if one engages in creative endeavors, either internally (creating with imagination) or externally (experiencing others' creations through fiction, movies, plays, etc). This seems less correct, like I'm stretch to apply the quote another way.
I collect quotes, but this is why I usually don't try to explain why I like them. I end up feeling confused and flustered, suspect that I don't quite understand what the writer was trying to say, and ultimately decide that maybe I don't like the quote all that much anyway.