At the end of Chapter 4 of Mind and Cosmos, Thomas Nagel finally turns to his candidate for best solution to the problem of consciousness:
I am drawn to a fourth alternative, natural teleology, or teleological bias, as an account of the existence of the biological possibilities on which natural selection can operate. I believe that teleology is a naturalistic alternative that is distinct from all three of the other candidate explanations: chance, creationism, and directionless physical law. . . . Teleology means that in addition to physical law of the familiar kind, there are other laws of nature that are “biased toward the marvelous.”
A teleological bias in physical law means that the laws governing all fundamental interaction would tend to produce outcomes that favor life and consciousness. But, according to Nagel, such a bias could not be expressible in reducible physical law:
The idea of teleology as part of the natural order flies in the teeth of the authoritative form of explanation that has defined science since the revolution of the seventeenth century. Teleology would mean that some natural laws, unlike all the basic scientific laws discovered so far, are temporally historical in their operation. The laws of physics are all equations specifying universal relations that hold at every time and place among mathematically specifiable quantities like force, mass, charge, distance, and velocity. In a nonteleological system the explanation of any temporally extended process has to consist in the explanation, by reference to those laws, of how each state of the universe evolved from its immediate predecessor. Teleology, by contrast, would admit irreducible principles governing temporally extended development.
The challenge for any teleological based theory is whether such time-dependent changes in physical law can be experimentally detected. If such goal-based bias cannot be detected in physical law, then teleology is essentially a faith-based system. Experiments to detect time-dependent changes in physical law have so far come up empty. So, the effect is very small if it exists at all.
I also think there must be some time-dependent effects in physical law, otherwise how could order producing organisms be created in a universe where unguided physical law seems to favor an increase in disorder. Of course, Nagel believes such effects are attributable to “naturalistic” effects and I think they are attributable to an ordering power at work in the universe. The difference is that an ordering power could be interpreted as evidence for God and a naturalistic approach would favor a non-theistic interpretation. The advantage of Nagel’s interpretation is that atheists can embrace the evidence for an order producing power without directly naming it or considering it evidence for God.
The main weakness in the current atheist argument is the denial of an active ordering power in the universe. This position flies in the face of common sense and puts atheism on the defensive, relying on arguments based on the problems with religious institutions. This may seem like a strange thing for a believer in God to say, but atheists need a strong metaphysical argument for the naturalistic position so that faith-based institutions will take seriously their arguments about the failings of religion. Nagel provides that metaphysical basis and atheists would do well to pay attention to him.
However, others have criticized Mind and Cosmos because Nagel fails to garner support from science for his position. (See, for example, https://chronicle.com/article/Where-Thomas-Nagel-Went-Wrong/139129/.) Such support does indeed exist and Nagel’s failure to include references to the science means that his argument is weakened. In fact, even Nagel’s summary of the book in the New York Times seems to step back from the teleological argument because he does not mention it: http://opinionator.blogs.nytimes.com/2013/08/18/the-core-of-mind-and-cosmos/?smid=pl-share.
And then there is the charge that Nagel has been too soft on the theistic option. I don’t find him soft on theism so much as failing to put forth the standard arguments against religion. The arguments against religion consist almost entirely on the problems that religion can cause among its adherents plus the incomprehensibility of religion from the point of view of non-theists. But arguments against religion are not arguments against theism so I find this criticism out of place.
Of course, Nagel does admit that his teleological explanation does not definitively rule out a theistic interpretation. But he correctly points out that theism seems like an unnecessary complication if the naturalistic explanation is sufficient. This is where I think the argument between believers and atheists should be: to what extent is the naturalistic explanation sufficient to account for human subjective experience? I think that a naturalistic teleology in particular and atheism in general will fall short of satisfying the deep human yearning for spiritual truths.
That is probably the real reason that Nagel’s atheistic critics do not like his book. A proper debate on the merits of the atheist position looks very weak unless some sort of ordering power is conceded. But conceding an ordering power seems to be conceding too much because it can be mistaken for evidence of divinity. However, Nagel maintains that atheism is a viable alternative if one views the ordering power as a natural teleology that is not subject to divine control. In this position he does not waver.