Does the Drake Equation Make Sense? Part 2.

If life originates, and the planet where this happens continues to reside in the liquid water zone, does it evolve to intelligent life? Are there certain conditions which are prerequisites for intelligence to evolve? Would they be common among such planets, or rare?

In this blog, and certainly elsewhere, it is supposed that tool use, starting with fire, then stone and wood, leads to the increasing capacity of the brain of some dominant organism. An equation, similar in form to the Drake equation can be written for this process, involving the evolution of increasingly complex organisms, starting from the first thing to form which constitutes life, a membrane enclosing some proteins that reproduce in some way, and which also produce more membrane. The steps might include the formation of more complex cells, with different features, the ability to exist in different environments and to consume different chemical energy sources. Then the shift to multicellular organisms has to happen, and many steps of evolution might be inserted into the new formula for the progressive development of capabilities of multicellular organisms. Then, back to single celled organisms, a step has to exist to be able to take energy from photons from the star, with the development of some primitive form of chlorophyll. And it goes on and on, as evolution is a horrendously complicated sequence. Regrettably, we do not understand the sequence completely, not even the conditions on the surface of the planet which are required to allow them to happen. The overall probability of producing intelligent species might be 1.0, meaning inevitable, or 0.000001, meaning intelligence is not a particularly useful capability for most creatures on an exo-planet.

The rise to intelligence is perhaps the most difficult of the probabilities in the Drake equation to estimate, as the evidence of most forms of life does not last for billions of years, with only a few exceptions. It should be one of the first orders of those who study it to come up with the new sets of probabilities, so that these can be studied from a normative sense, and then the whole combined into the Drake factor measuring it.

From intelligence to a civilization, mastering technology up to electronics, is another opportunity for sub-probabilities to be estimated. Here it is much easier, as there is history of our development, and it serves as one example, and a base upon which tangents may be followed. This blog includes, in many of the posts, speculation on the steps involved. There seems to be a natural order by which technology progresses, one stage depending on the previous, and there also seems to be a drive, reminiscent of evolution, which pushes creatures to develop successive stages of technology. Figuring out the steps up to the stage of civilization that we currently inhabit is not so difficult, but the postulation of what happens next is extremely controversial. There seems to be a tendency among modern-day humans to forecast dooms that might be imminent, and if one such doom really exists and is universal among intelligent species, reaching broadcast capability might be chancy, and staying there more chancy.

Another of the assumptions inherent in the Drake equation is that broadcasting is the end point of technology, and it would continue for some long period. It hasn't. There is still some, but the term, L, in the Drake formula may be very short as better ways of shipping large quantities of information around the planet have been found and have displaced broadcasting. This seems likely to continue, so L may be, for us, less than a hundred years. With that short a time, being so lucky as to be listening during the particular century out of billions of years of planetary existence is almost impossible to expect.

The Drake equation, if used with the retrospection of all the decades that have passed since it was first written down, may well indicate that the SETI project is hopeless and should never have been attempted. Many people's lives and careers were involved in it, and certainly some, perhaps many, were overwhelmed by the feelings that if they were successful, their fame would be writ large on the pages of scientific history. Some of the participants talked about the success of the project being a grand changer of the direction of human civilization. With such a result, it is not hard to see how the Drake equation was mis-evaluated in many ways so as to provide a justification for the search. Who wants to have their hopes of a glorious legacy be dashed?

The Drake equation, and indeed the SETI project, did have the value of focussing the attention of many individuals, scientist and non-scientists, on the various steps in the formula. It raises the interest level and provides some motivation for doing the hard scientific work necessary for our continued progress. There is little work going on in some very important areas, such as questions of the origination of life, but there might be even less if the burst of energy and excitement that the SETI project ignited had not happened. Understanding evolution is a continuing scientific task, and it might not have been greatly affected by SETI's popularity, but perhaps as the gaps and uncertainties in Drake's formula become more clear, there will be some effect, and some new Darwins will enter the field and erase the dark gaps in the theory.

Mankind has always tried to understand history, and the nature of man and the nature of civilization, but the Drake equation takes all this non-scientific palaver and demands that it be turned into a quantitative measure of how civilization develops. Historians typically do not make much use of the theory of technological determinism, which says that civilization is forced to adapt to technology, which is forced to follow a certain pattern of temporal stages. If history becomes scientific, this might be the result of the Drake and SETI activity with the greatest influence on the future of humanity. Once history becomes more scientific, a better forecast of the potential futures can be given and we would not have to resort to choosing between a dozen different predictions of dooms.

To summarize, the Drake equation inspires work in the following areas: orbital stability for small rocky planets, origin of life from either a unique event or ordinary conditions, the evolution of life through the millions of steps needed to lead to intelligent creatures, and the transformation of history from an art to a science. With the retrospective understanding we now have, the probability of success of the SETI project likely starts with many zeros, and there does not seem to be any redeeming factors in the equation which would raise it even to the order of a few percent or more. Given the amount of effort that was put into it, it was a good start, insofar as it provides motivation for more good science, and also makes non-scientists aware of the possibilities that we are not alone, and with a good amount of further work, we might know just how not alone we are.