Elliott Sober: The big picture, I think, is that common ancestry is ev...

Evolutionary biologists often appeal to parsimony when they seek to explain why organisms "match" with respect to a given trait. For example, why do almost all the organisms that are alive today on our planet use the same genetic code? If they share a common ancestor, the code could have evolved just once and then been inherited from the most recent common ancestor that present organisms share. On the other hand, if organisms in different species share no common ancestors, the code must have evolved repeatedly.

Elliott Sober

live-for-today example hands

Evolutionary theory, properly understood, does not conflict with the idea that God occasionally intervenes in nature - for example, by once or twice causing a beneficial mutation to occur. Biologists have not detected any such interventions despite the data and theory they have assembled about mutation. However, I think it is a mistake to expect biological experiments to be able to detect such one-off acts of divine intervention, especially if those acts occurred in the distant past. Science isn't in that line of work.

Elliott Sober

mistake past thinking

Unfortunately, philosophers of science usually regard scientific realism and scientific anti-realism as monistic doctrines. The assumption is that there is one goal of all scientific inference - finding propositions that are true, or finding propositions that are predictively accurate. In fact, there are multiple goals. Sometimes realism is the right interpretation of a scientific problem, while at other times instrumentalism is.

Elliott Sober

doctrine goal facts

Evolutionary biologists often avoid using the term "race" because there is so much racist baggage that comes with the term. However, they are often okay with the idea that the genealogy of human groups within our species can sometimes be inferred in much the same way as the genealogy of different species.

Elliott Sober

race way ideas

When one theory is simpler than its competitor, this fact is relevant to saying what the world is like.

Elliott Sober

theory facts world

I think that some "interventionist theisms" are compatible with evolutionary theory. (By "intervention," I don't mean that God violates laws of nature; I mean that God affects what happens in nature in ways that are additional to the ones that deism recognizes.)

Elliott Sober

law mean thinking

I think that the existence of Beethoven is remarkable, but I do not bristle at the suggestion that this event had a low probability given the initial state of the universe.

Elliott Sober

suggestions events thinking

The rabid opposition to group selection has now considerably subsided. In the process, the conceptual structure of evolutionary theory has become clearer, as have the relationships that connect different theoretical approaches.

Elliott Sober

groups structure different

Darwin repeatedly used the hypothesis of common ancestry as a platform on which to build his various ideas about testing hypotheses concerning natural selection. He also argued that adaptive similarities provide little or no evidence for common ancestry. Although this second claim needs to be fine-tuned, Darwin was right that ample evidence for common ancestry can exist even if none of the characteristics we observe were caused to evolve by natural selection.

Elliott Sober

ancestry littles ideas

Current organisms have a higher probability of sharing a single code if the common ancestry hypothesis is true than they'd have if the hypothesis of separate ancestry were true. That is, the simpler hypothesis has the higher likelihood in the technical sense of "likelihood" used in statistics.

Elliott Sober

ancestry statistics common

Deism is logically compatible with evolutionary theory for the simple reason that the theory says nothing about the origin of the universe or of the laws of nature.

Elliott Sober

simple law reason

"Simpler is always better" is an overstatement.

Elliott Sober

overstatement

Creationists have long held that evolutionary theory is atheistic; defenders of the theory do the theory no favor when they agree.

Elliott Sober

favors theory long

"Methodological naturalism" and "metaphysical naturalism" are terms that often surface in the continuing battle between evolutionary biology and creationism/intelligent design. The methodological thesis says that scientific theories shouldn't postulate supernatural entities; the metaphysical thesis says that no such entities exist. In this debate, God is the supernatural entity at issue; the question isn't whether science gets to talk about mathematical entities if Platonism is correct.

Elliott Sober

issues design intelligent

In the history and literature courses I took, epistemological questions came to interest me most. What makes one explanation of the French Revolution better than another? What makes one interpretation of "Waiting for Godot" better than another? These questions led me to philosophy and then to philosophy of science.

Elliott Sober

literature waiting philosophy

I disagree with those who argue that evolutionary biology and the existence of God are incompatible.

Elliott Sober

biology existence arguing

If you have evidence that C1 is a cause of E, and no evidence as to whether C2 is also a cause of E, then C1 seems to be a better explanation of E than C1&C2 is, since C1 is more parsimonious. I call the version of Ockham's razor used here "the razor of silence." The better explanation of E is silent about C2; it does not deny that C2 was a cause. The problem changes if you consider two conjunctive hypotheses.

Elliott Sober

silence doe two

Earlier attempts to show that simpler theories always have higher prior probabilities have failed, but there is a restricted circumstance in which the claim is right.

Elliott Sober

theory claims circumstances

This is not to deny that there are versions of theism that do conflict with evolutionary biology. Young Earth Creationism is an example; it claims that God created life on earth within the past 10,000 to 50,000 years. But other types of theism are different.

Elliott Sober

example past years

Some philosophical arguments (e.g., in connection with the mind/body problem) look pretty good, while others (e.g., those that criticize moral realism) do not.

Elliott Sober

philosophical connections mind

The big picture, I think, is that common ancestry is evidentially prior to natural selection in Darwin's theory and in contemporary evolutionary biology as well.