There are a series of Probaway posts on unknowns and unknown unknowns, with the effort being to isolate the factors that might be helpful in discovering knowable things within the presently unknown areas. This is a meta science, an overview of a search strategy. The idea of shadowing volumes as a way of revealing unknown things within their umbras may be useful. It consists of blocking the brilliance of sources so the more delicate things may be viewed, and then blocking second and third sources covering a given area with their brilliance, and that are creating obscurity because of their brilliant noise. Some unobserved things may simply be too small to reflect much illumination or cast a shadow, or not big enough to cast a shadow or too transparent to be seen or cast a shadow. These unobserved objects might be tiny or very big, but too diffuse in the ordinary glare of various typical illuminators to be seen. All the same they may exist, and may have interesting or perhaps useful properties. Perhaps the usefulness of this technique would be in discovering places where there isn’t anything, in case the absence of something is valuable. This is a kind of Karl Popper-like search for the negative of tested observations, in that it is using falsifiability as the starting point, as opposed to using it as an ending point proof of the not quite rightness of a theory.