Spoiler Thread: Avengers Infinity War

There's a theory that since Dr. Strange could see the timeline/possible future where Thanos is defeated, he must not be all the way dead. The Ancient One said that “I’ve spent so many years peering through time, looking at this exact moment, but I can’t see past it. I’ve prevented countless, terrible futures. And after each one there’s always another. And they all lead here…” and that she could never see past the moment of her own death. Here's a page discussing the Ancient One vs. Dr. Strange, and if it's not the exact page where I first read about this idea, it covers largely the same ground.

Since Dr. Strange seems to have seen past the snap, then he must just be mostly dead.