All evaluations are comparisons. When they are not phrased as comparisons–some thing is said to be good or bad but is not explicitly compared to some other thing–this just means that the comparison is implicit. The other half of the comparison is left blank. Something is there, but it is not stated and there is a good chance we are not consciously aware of what is there or even of there being a “there”. Hemianopia, a recurring theme in the writing of Oliver Sacks, provides a wonderfully explicit analogy. People with hemianopia are blind in half of the visual field. This is very different from being blind in one eye. Suppose you are blind in the right half of your visual field. The visual field of your left eye has a right half of its own, and includes part of the right half of your total visual field; these would be missing. The defect has to be in visual processing. In effect, half of the visual data are being sent for analysis to a processing center, and nothing (at least, nothing the person is conscious of) is coming out of that processing center. The right half of the visual field is not black, it is absent. Black would be a signal, at minimum an indicator that there is a shelf in consciousness labelled “right visual field”, and when one directs attention to that shelf one finds it empty. Sacks describes people with hemianopia insisting that a plate is empty when the left half of the plate is empty. They do not think to themselves–“Well, I can’t see the right half of my visual field, so if I look a bit further to the right I can see the whole plate.” They don’t know the plate has a right half that could be seen. So, imagine we are sometimes like that when we conduct evaluations. We say that a thing is good. Good compared to what? Much of the time, we don’t know. That half of the comparison isn’t garbled or blank, it is absent.

We could also compare this to a missing frame of reference. Suppose we see an object moving to the right. That motion is relative to some frame of reference, some thing or set of things that is interpreted as being fixed in position and relative to which the object is moving. In most ordinary social interactions, one frame of reference is so consistently the obvious default that there is no point stating it and it can be simply assumed without trouble. Sometimes, though, it is not clear. One person may intuit one frame of reference, the other a different one. Then, for effective communication, the first necessary step is the realization that “frame of reference” is a shelf in consciousness that has something on it and could have something different on it. If that shelf is simply invisible, we are stuck.

When we aren’t even aware of the shelf, we haven’t considered what objects should be on it. An implicit comparison is very likely to be unhelpful or misleading. We act as though we are making an appropriate comparison when we aren’t even aware we are making a comparison. Once we are aware of the shelf and consider what should be there, I think a general rule is that the relevant scope of analysis is the range of variation that can be proven to exist. When, for example, one finds oneself thinking that every vote is a vote for the lesser of two evils, there is some unspoken good candidate that–since this candidate never seems to appear–is probably well outside the range of meaningful analysis. One could just as well put an unspoken bad candidate, representing a degree of evil never seen in society, on the shelf and judge every candidate a saint. There’s no reason to prefer one over the other. In either case, we might look at our ruler and wonder why it is marked out to 12 inches when every single thing we measure is less than 4 inches long.

All arguments based on unspoken comparison make this kind of error. When a comparison is explicit, of course it’s still misleading or useless much of the time. We should simply treat implicit comparisons as meaningless until they become explicit, and then consider if the comparison is accurate and meaningful. People hate to abandon the ghosts of better worlds. It feels like abandoning hope, but can mean abandoning despair.

I thought I had about three sentences to write, to capture something that seemed interesting enough to pin down, and find myself somewhere else.