Hello folks, I am poking my head in here for the first time at the polite request of my friend Randy. This discussion makes me see how much I am missing. Having near-adolescent kids, I am concentrating too much recently on the dangers of the internet, and need sometimes to be reminded of the wonderful benefits.  Forums like this have to be near the top of the list.  Still, in the days of Johnson, Boswell, and Goldsmith we'd all be discussing this in someone's living room, but here we are now in cyberland. So be it. Anyway, I would say that in nearly any introductory science program we have to put up with generalities that are violated by a few specific examples.  This is especially the case in biology where every category is violated by the realization of a continuum (a theologian should investigate the importance of this lesson).  But it is also the case in physics where general rules are violated either by mundane things like friction or in situations when things are very small or very large.  So I do not fault Tyson or anyone else for describing evolutionary change as being given scope by mutations whose existence and specific nature are independent of their outcomes, in the same way that the causes of a landslide are independent of what gets squashed or accreted downhill. It is the responsibility of each producer/writer/performer to decide how much of the complexity in life can be presented in a particular format to a particular audience in a particular amount of time. I myself teach to my introductory undergrads that mutations are random with respect to outcome, then merely mention that there are some exceptions they might learn later; whereas I teach to doctoral students the current state of knowledge of the complexity. Still, there is no known case to my knowledge where the specific mutation, as opposed to the likelihood of mutation, is driven by outcome. In other words, we might predict and discover genes that are high-mutation and genes that are low-mutation, in terms of the accuracy of copying, based on the functions of those genes and the variability of the relevant environmental features (by the way these predictions derive directly from evolutionary theory, although I admit that the framers might not have realized this). Mechanisms to assure that DNA replication is accurate are themselves products of, and thus subject to, natural selection. Of course, for point mutations we have a limited array of possibilities, and as far as I know a situation has not yet been discovered where an A can be predicted to mutate into a T in a particular environment. In other words, mutations might only have been "directed" to the extent that certain genes are more or less accurate in their replication, period (and this rarely, as far as we know).  Transposon activation might be a technical exception, but even here we cannot predict the specific change. Still, I would be among the most excited and bright-eyed readers of an article that reported the discovery of a mutation that was very specifically guided by the current environment, in order to produce a phenotypic effect that was advantageous in that environment. Such would be worthy of a Nobel prize (although unfortunately our category doesn't exist, as I am reminded repeatedly by ambitious colleagues). Such a discovery would be perfectly fine in the sense that it wouldn't cause the sky or evolutionary biology to fall, much less reasonable theological theories. One can imagine (and this could be modeled) the possibilities for natural selection to result in the increased likelihood of very specific chemical changes that produce particular mutations leading to specific phenotypic effects.

Ok, I mentioned theology, but before I go there briefly, I just want to reiterate Randy's enlightening yet humble (I am always deeply inspired by Randy's humility) suggestion that when evolutionary biologists refer to random mutation they mean random with respect to outcome. I certainly would go out on a limb to say that random in this context entirely, and I mean entirely, means random with respect to the outcome, and specifically whether the phenotypic outcome of a genetic mutation is advantageous or not. There is not an evolutionary biologist worth his or her salt who claims that randomness means independent of the environment impacting the genes. Of course mutation has to be caused by something in the microenvironment of the genes, whether it is a localized deficiency of the appropriate base during replication, a trace amount of some chemical in the cytoplasm, ultraviolet radiation causing thiamine dimers, or whatever else. This is a fledgling area of biology, and a very exciting one-- the causes of mutation-- but we will certainly continue to uncover the reasons, in terms of physical causes in the environment of the genes, why any particular gene mutates the way it does. The problem in any particular case, of course, is to explain why a singularity happened in the past, however recent. This is a problem in any sort of scientific explanation. But we all agree, including the most "fanatical neo-Darwinists" (of which I am not sure whether I ought to be considered one), that every mutation, every single mutation, has a physical cause. In fact, one aspect of the temptation to become a fanatical neo-Darwinist is the commitment, an almost religious commitment to the point of yikesitude, to the regularity and uniformity and exclusivity of physical causation.  These aren't the people invoking indeterminacy based on the uncertainty principle in quantum mechanics, much less postmodern ideas of the fundamental incompleteness of the physical universe as described by science. Fanatical neo-Darwinists are among the ones who are saying that physicalism says it all and that we should in principle be able to explain everything on this basis. I think they're wrong, but I agree with them in their faith, or a bet (for me it is just a bet) that all mutations have physical causes. Therefore the sense in which biologists use the term "random" must exclude the radical one meaning a lack of influence or cause located in the makeup or environment of the genes. For my part, I'd bet my life that any particular mutation's physical cause could be identified if we had a way to record the sequence of events.

As for theology, I am out of my depth so I can only offer my opinion that the extent to which mutations are random, in the sense of being uninfluenced by the advantage of their outcome for the bearer, has no relation to the nature or existence of God. The idea that "explained regularity" is automatic and doesn't require God, whereas the inexplicable and unexplained indicates or provides an opening for divine action, is a theology for which I have no time. I have lived with it in my (fundamentalist) family and my (evangelical) church and my (Catholic) biology teachers my whole young life and I have had thoroughly enough of it. I haven't the faintest idea why so many Christians must be anti-science in the sense of failing to understand or accept evolution, and yet at the same time so inappropriately reverent of science as to give it the power to usurp God merely by describing that something has a certain regularity. And I somewhat understand but strongly disagree with the accompanying view that God's action is more special or significant or meaningful or spiritually potent when it is accompanied by inexplicability. We should combat this tendency to invest natural explanation with the power to disenchant.  The end of that road is the terrible view that ignorance is blessed and knowledge an evil. I believe that we should conclude nothing at all about the meaning or importance of divine action on the basis of whether we can understand it physically-- nothing at all. Miracles in the Bible are exceptions precisely because the state of being exceptional functions as an object lesson for us; they are not manifestations of a split divine personality, much less a polytheistic conflict between one god wanting to do something now and some other power that is responsible for the ordinary operation of the universe. Thus even the examples of apparent divine self-contradiction appear as such solely for our benefit (and in most cases we are a vain generation for needing them). Returning to natural processes such as mutation, do we really want to see them as either divine self-contradiction or implicit polytheism?! Whether mutations are "random", and what that word means, has in my view no theological importance whatsoever. Divine action will occur, cosmic Architecture will proceed all the same, whether or not we do, or ever will, understand the mechanism.