Now that I think about this metaphor again, I think there is a problem with the word "observable" -- it is actually the same as "selected". A camera cannot capture everything that is going on, just like your own "sensors" cannot capture everything. Words like "observable data" or "available data" suggest that we do not have to look outside the box for data that is currently not observable or available. The ladder must be resting on something called "reality" or "data pool" or "infinite universe" or something like that. It is from this pool that we start selecting with our sensors. In order to expand our sensors, we need to understand that there is much more out there.