One might imagine perhaps that while there could in principle be methods of perception that would recognize features beyond, say, repetition and nesting, any single such feature might never occur in a sufficiently wide range of systems to make its recognition generally useful to a biological organism.

But as of now I do not know of any fundamental reason why this might be so, and following my arguments in Chapter 8 I would not be at all surprised if the process of biological evolution had simply missed even methods of perception that are, in some sense, fairly obvious.

So what about an extraterrestrial intelligence? Free from any effects of terrestrial biological evolution might it have developed all sorts of higher forms of perception and analysis?

Of course we have no direct information on this. But the very fact that we have so far failed to discover any evidence for extraterrestrial intelligence may itself conceivably already be a sign that higher forms of perception and analysis may be in use.

For as I will discuss in Chapter 12 it seems far from inconceivable that some of the extraterrestrial radio and other signals that we pick up and assume to be random noise could in fact be meaningful messages—but just encoded in a way that can be recognized only by higher forms of perception and analysis than those we have so far applied to them.

Yet whether or not this is so, the capabilities of extraterrestrial intelligence are not in the end directly relevant to an understanding of our own experience of the world. In the future we may well manage to use higher forms of perception and analysis, and as a result our experience of the world will change—no doubt along with certain aspects of our science and mathematics. But for now it is the kinds of methods of perception and analysis that we have discussed in most of this chapter that must form the basis for the conclusions we make about the world.