I can't tell you why, but I can point out that all of the other gaps are about how certain experiences correlate with each other (and let's face it, all measure

I can't tell you why, but I can point out that all of the other gaps are about how certain experiences correlate with each other (and let's face it, all measurements I make are made known to me by experiences I have), whereas this one is about why anything is experienced at all.