Re: "Web-mediated SETI": Robert Bradbury Replies
Thu, 4 Nov 1999 10:05:19 -0800

Robin Hanson, <>, writes:
> In the space of all logically imaginable observations, the
> dead universe theories have, as a whole, assigned a relatively
> high likelihood to data we observed, relative to the data
> we did not see. In Bayesian terms, relative to theories which
> don't assign as high a likelihood to to observed data,
> our posterior that the right answer is in this theory class
> should rise.
> In contrast, the class of living universe theories has not,
> as a whole, assigned a very high likelihood to the data we
> actually observe. For every more specific theory that predicted
> that, say, the allies would win World War II because God is
> on their side, another nearly equally plausible theory in
> this class predicted the opposite.

The way I am applying this Bayesian argument is with regard to reports of events which would seem to imply a "living" universe, i.e. one in which intelligence intervenes to apparently circumvent natural law, in the form of events which have been described in terms of miracles and magic.

Given the success of dead-universe predictions, we come to believe that these reports are very likely to be incorrect. The reason we disbelieve these reports is exactly because of the evidence that the universe is dead, and therefore natural law holds in a relatively simple and straightforward manner. (Of course, natural law holds in a living universe as well, but the point is that Powers would be able to use their technology to give the illusion of violating virtually any laws.)

Now if we develop new reasons to believe that the universe may be living, such as the Fermi paradox or Robert's attempts to explain our cosmological observations in terms of widespread alien activity, then we have to re-evaluate our earlier decisions regarding miraculous events. To the extent that we come to believe that the universe is living, it very likely would have been so throughout recorded history. And therefore we can no longer interpret history as occuring in a dead universe.

In the context of a living universe, our reasons for disbelieving in miracles no longer apply. Miracles are no longer impossible, as they would be in a dead universe.

Strictly speaking, Bayesian reasoning merely forces us to raise the probability that miracles may be real, given new reason to believe in a living universe. By itself this is a weak statement, as it may be argued that the necessary increase in probability is trivial, from one in a quadrillion to two in a quadrillion, or some such.

I am arguing though that the fundamental reason for disbelief in miracles is that the universe is lawful, and therefore if the universe is living this fundamental reason no longer applies. Therefore the whole issue of miracles must be reevaluated from the beginning, without the preconceptions and mindset which we carried over from when we thought the universe was inherently lawful.

Now, you can still disbelieve in miracles, as we have seen here: people can create explanations in terms of the apparent motives of the Powers which (we stipulate) are present. But any such argument is far weaker than one based on natural law. Judging the psychology of unknown super-intelligences can be at best a highly uncertain enterprise. There is no way that I can see to justify a strong disbelief in miraculous intervention given a worldview that includes godlike aliens in our vicinity; at least such disbelief can be nowhere near as strong as that which would hold in a dead-universe model.

My basic point, therefore, is simply that to the extent that you come to believe that a local alien presence is a real possibility, you should accept that divine and magical and mystical events reported in the past (and present) may be true. The same thing would hold, BTW, if you came to believe that time travel from the future were possible, or that we were part of a Tiplerian simulation where there could be intervention from the outside.

The lessons to draw from this are more ambiguous. I do not mean to say that we should refuse to accept local Powers because it forces us to believe in religion. We should follow our beliefs whereever they take us, courageously, and let the chips fall where they may. However, we have to let the chips fall! No one here should be bashing religion, or even be especially skeptical of religious reports, pseudo-science, Big Foot, UFOs, or any of the other phenomena which seem to defy the laws of nature, if they are seriously entertaining the possibility of a localized alien presence. It is inconsistent to adopt a position of extreme skepticism with regard to one set of reports while openly exploring the other possibility.

Furthermore, I think it is important to recognize a possible emotional component which may be driving beliefs in alien Powers. There are many commonalities between such beliefs and those of traditional religions. Throughout SETI literature you can find similarities between the appeals to the wisdom, benevolence, etc. of the aliens, and traditional appeals to God. I'm not saying that all believers in the value of SETI are looking for God, but I do think that in some cases there are similar motivations involved, perhaps subconsciously. We should all try to be aware of our emotional motivations so that we can make better decisions.

To the extent that SETI efforts represent a sublimated search for God, hidden beneath rationalism, then my arguments will be especially unwelcome. Some SETI believers think they have cast off the chains of religion, and are likely to be an extreme skeptics with regard to classical religious stories. They will abhore any suggestion that they have inadertantly adopted a doctrine which requires them to be open to the possibility of the truth of biblical miracles.

The emotional aspect goes in the other direction as well. I personally experience tremendous emotional resistance in accepting the possibility that Biblical miracles may be true. I do think this is a component of my skepticism towards the suggestions by Robert and others that aliens may have a widespread presence in the galaxy. I tend to be impatient and disdainful of the SETI enterprise; it seems only slightly removed from praying at the temple. The recent "Welcome to ETI" web page serves for me as practically a reductio ad absurdum with regard to the quasi-religious nature of SETI efforts.

In either case, then, there can be a significant emotional component in our attitudes towards SETI, whether supportive or skeptical. Hopefully we can all try to make ourselves more aware of them and thereby gain clarity in our judgements.