Well, I didn't say we could do it reliably. :-) But we can do it. You can look at something and say, "It's green" and I can look at the same thing and agree, "Yes, it is green." And then we can look at the same thing a minute later and say, "It's still green." The remarkable fact is not that we can do this 100% of the time, but that we can do it at all.