Suppose insects are conscious. There are at least about a billion insects per human being. So, if insects are conscious, we should be surprised to find ourselves not being an insect. But if insects are not conscious, there is no surprise there. So, it seems, observing that we are not insects gives us very strong evidence that insects are not conscious.
But this just doesn’t seem to be a good argument… Perhaps the self-sampling thesis—the thesis that we should count ourselves as randomly selected from among observers—needs to be restricted to intelligent and not merely conscious observers? But isn’t that restriction ad hoc? If we're doing such restricting, maybe we should restrict even more finely, say to observers at our exact level of intelligence?