Historical evidence and Science

I was just listening to a caller on an old episode of The Atheist Experience (about 1 hr 3 min in – I love that show). The caller was quite disingenuous, asked Matt and Jeff what their degrees were (they have none), went on to present his own bona fides (computer programmer “degree”), and then asked what their proof was for the origins of the universe. Matt headed the caller off at the pass quite nicely. He said (quite rightly) that that did not matter, since even if we had no explanation this lends no credence to any other hypothesis. Competing ideas are simply not necessarily equal in terms of their truth value, and just because someone considers one false does not make their own idea true, unless we are speaking of a true dichotomy (which this most definitely is not). A further problem is the caller desired “proof”. The only place the word “proof” is applicable is in mathematics and logic. In the natural sciences, conclusions are drawn based on evidence – we do not deal in “proof”.

The caller also committed another fallacy, claiming that if we do not observe something directly then it is not scientific. We did not observe the universe come into existence, therefor we can not say that Big Bang model is correct. That is patently absurd. All experiments – even those in a laboratory – are indirect measurements. When we mix chemicals in order to observe how they react, we are not directly looking at the individual molecules. We might see a color or temperature change in the mixture, but does the fact that these are indirect observations of what is going on invalidate the idea that a reaction has taken place? Even if we identify the product, it is still historical even if it happened only a few minutes ago. Historical evidence is simply another type of indirect observation. Jeff made a good point that since we have only known of Pluto’s existence for about six decades – far less than it takes Pluto to make a complete orbit – the caller must conclude that we can not know that Pluto orbits the sun!

Think of it this way. You come home to find the family cat looking guilty in front of an overturned plate of unsecured leftovers. There are many possible explanations for this scene, but are they all equally likely? Perhaps it was death rays from Mars – in a plot by Martians to assassinate my cat who is secretly the only thing standing between us and a planetary invasion – missed, the rays striking the plate on the counter sending it careening onto the floor. Does anyone really think that this explanation is on a par with the possibility that the cat (in its gastronomic zeal) pushed the plate off the counter and followed it onto the floor to finish off the leftovers? I don’t think so. Yet each explains the scene fully.

The truth is, each and every one of us uses historical evidence daily, yet this caller chose to claim that in this specific instance – coincidentally one in which he found it convenient to do so – one could not validly arrive at a scientific conclusion in this manner. This is obviously nonsense. Certainly, the caller is correct in one aspect – that we did not directly observe the Big Bang event. But this event gave rise to observable consequences. From astronomical observations (such as Hubble’s observation of a red shift proportional to the distance a galaxy is from ours) and particle physics cosmologists have built a model to explain what they see. Even more importantly, this model makes testable predictions – observations that weren’t been made at the time the model was proposed but what would be expected to be observed if we look, such as the cosmic background radiation and relative abundance of primordial elements such as hydrogen, helium and lithium.

Evolution as Darwin presented it similarly relied on historical evidence (it no longer does – evolution is being observed in action, such as the Pod Mrcaru lizard introduced onto the Croatian island in 1971 for this specific purpose). Predictions came fast and furious. It was hypothesized that horses evolved from mammals with more than one toe. This hypothesis was rapidly followed by its confirmation, particularly from North American fossil finds. There have been thousands of such finds. The whale evolved from a land mammal and its fossil lineage is incredibly well defined, right down to our ability to see how the position of the nasal passage moved from the front to the top of the head. Lineages derived from comparative morphology match those derived measuring genetic differences as predicted by the modern synthesis. These evidences all confirm predictions made by evolutionary theory and thus strengthen it greatly.

In short, conclusions based on historical evidence are perfectly valid and scientific. The only difference between doing an experiment in a lab and drawing conclusions from historical evidence is that there are tighter controls and a greater ease in adjusting variables in former. That’s it. The Earth, the universe- these are laboratories and nature itself has done the experiments. In both situations we are observing the results and explaining them. Rejection of this always seems to be associated with an incompatibility between closely-held ideas and reality. For those who deny evolution and Big Bang cosmology, grow up. If you think that when science conflicts with a held belief, so much worse for science, then you have abandoned reason and the only thing left which might get through to you is mockery.

Matt had as good a response. He hung up on his ass.