Design

If we look back at the history of natural theology we find that there is an ancient tradition of trying to draw teleological conclusions about the nature of the Universe from the structure of the Universe.Despite the superficial diversity of content and sophisticated in these Design Arguments -- some arguing for the existence of a Designer, some for the anthropocentric purpose of the Universe, some for optimality of the Universe in different senses -- they can be neatly classified by means of our distinction between laws and outcomes. The oldest and commonest Design Arguments are about fortuitous coincidences in the world of outcomes: the fact that animal needs seem to be so well met by their physiologies and habitats, that the geology and motion of the Earth is conducive to the presence of life, that the eye is so remarkable an optical instrument, and so on. These arguments were particularly commonplace in the eighteenth and early nineteenth centuries and are particularly simple to state. As a result they were extremely persuasive and their seductive power is still in evidence today. The flaws in the arguments based upon them are logically subtle and rarely persuasive to non-scientists (a state of affairs that some biologists find exasperating). 

However, in the living world the discovery of the power of evolution by natural selection provided a simple alternative explanation for the many remarkable examples of apparent design in Nature that the proponents of this form of the Design Argument had so carefully documented. Indeed, this collection of examples of adaptations had played an important role in stimulating Darwin to find an explanation for them. The other stream of Design Arguments, which became fashionable in Newton’s time, were based upon the nice structure of the laws of Nature. Sometimes they were called eutaxiologica Design Arguments. Newton’s discovery of laws of motion and gravity provided the impetus and scientific basis for this type of Design argument. Richard Bentley’s Boyle Lecture provided the first public platform for argument of this sort. They appealed to the rationality, symmetry, special form, and simplicity of Natures laws as evidence for a Designer. This type of Design Argument is much more sophisticated than the first. You have to know about mathematics and physics to appreciate its force. You need to be able to work out the chains of consequences for human life of altering some aspect of the laws of Nature (for example changing Newton’s law of gravity). As a result it was less persuasive to non-scientists than the Design Argument based on the fortuitous relationships between outcomes. 

However, one can see that (unless the laws of Nature themselves evolve in some way that we do not suspect) natural selection does not affect this form of the argument. We note that many modern discussions in the God and the New Physics style focus upon this side of the Design Argument. This reflects the extent to which physicists who work on elementary particle physics and gravitation are Platonic in outlook. They see the underlying laws, symmetries, and mathematical structure of the physical world as the primary source of wonder and inquiry in their scientific work. I suspect that when it comes to this aspect of the Universe almost all physicists would say that the Universe is obviously ‘designed’, in the sense that it possesses order, it is not random, it is not a muddle of half-baked structures and unreliable laws. Where they would differ is on the issue of what the cause of such ‘design’ is. Why does it require a Designer? If it does what link can we make between this Designer and traditional concepts of God? These questions draw us off from the observational evidence along various directions of metaphysical speculation. However, we must be very careful when drawing metaphysical conclusions from the nature of physics. 

As if the intrinsic uncertainties in getting the physics right were not large enough, there is also an alarming non-uniqueness associated with these extrapolations into the metaphysical realm. Let me give one example of how deductions from the supposed nature of the laws can also be philosophically ambiguous. There can exist representations of physical laws that are equivalent in mathematical content and in the observational predictions they make, yet which diverge philosophically when some meaning is ascribed to them. A simple example is provided by laws of motion, like Newton’s. These are commonly presented as causal (non-teleological) laws: the application of the law to a present state determines the future. Seen like this there can be no teleological aspect: there is no final state that is fixing the trajectory of motion by means of some final state that is to be reached. However, we know that causal laws like these can be replaced by the requirement that some quantity (the action) be minimized when considered for all the possible trajectories that the motion might take between points A and B. This minimization principle chooses the same path from A to B as is dictated by the causal law of motion. However, the action principle formulation has a teleological aspect. The path is fixed by initial and final conditions being specified. Thus any interpretation of the form of the laws is fraught with ambiguity in this case.

Contributed by: Dr. John Barrow