A Weak Analogy
The argument from analogy is an inductive argument from order to design. Inductive arguments project observed regularities to similar unobserved cases. If every observed raven to date has been black then we are justified in inferring that the next observed raven will also be black. We are not, however, justified in inferring that the next observed bird will be black unless we have good evidence for believing that the next observed bird will be a raven.
Paley’s argument from design has the following structure:
The Argument from Analogy
(1) Ordered systems a, b and c have designers.
(2) The universe is an ordered system.
(3) The universe has a designer.
Paley’s argument thus projects an observed regularityâ€”the observation that certain ordered systems have designersâ€”to an unobserved case, namely that of the universe. Paley’s arguments thus rests on an analogy; it is only if the universe is relevantly similar to the ordered systems a, b and c that Paley’s inductive inference will be justified.
Whether the universe is relevantly similar to the ordered systems a, b and c is debatable. Opponents of Paley’s argument object that only the observation of various other universes with designers would provide a pattern of observations that would justify the inference that this universe has a designer. Observing other ordered systems, watches for example, to have designers isn‘t enough; the anology between watches and the universe is too distant to support a design inference. In fact, it is suggested, there are far better alternative analogies available, which point to very different views of the universe’s origins.
Defenders of Paley point out that the inference is from order to design, and suggest that it is irrelevant in what kind of system that order is found. Whether it be a universe or a watch, they say, the observation is of the same thing: complexity ordered towards a purpose. In every case, they suggest, this ordered complexity is evidence of the same thing: intelligent design.