“Scientists try to characterize a range of possible causes of evolution, and then to determine which of these possibilities actually obtained. The actual is understood by first embedding it in the possible.”

E. Sober, The Nature of Selection, rozdz. 1, s. 14 (PDF: 24). “Natural selection is one kind of cause. Selection can produce evolution, but there are other mechanisms that are capable of doing the same thing.”

E. Sober, The Nature of Selection, rozdz. 1, s. 19 (PDF: 29). “In the absence of some alternative plausible mechanism, the argument from design deserved to be taken seriously. Darwin’s contribution was to develop a nontheistic alternative.”

“When a characteristic becomes prevalent in a population, one possible explanation is that this happened in virtue of Darwinian selection among individuals. But as with any inference from effect to cause, we must recognize that a given effect may, in theory, be produced in various ways.”

“Selection for jaws will bring chins along as a free rider. [...] But if architectural constraints tie traits together in packages, the power of natural selection to produce novelty will be reduced.”

E. Sober, The Nature of Selection, rozdz. 4, s. 104-105 (PDF: 114-115). “The randomness of mutation does not mean that mutations are inherently unpredictable. [...] The defensible idea in the claim that mutation is random is simply that mutations do not occur because they would be beneficial.”

“The world we live in may simply be such that certain questions are very hard to answer. If so, the difficulties that biologists find in applying a theory may actually be a sign not of the theory’s imperfection but of its adequacy.”

“Since biological populations must be finite, there is no doubt that chance plays a role in evolution. The question that interests biologists is not whether this is true but how important the role of chance has been.”

“The propositions that allow an event to be predicted may fail to explain why it occurs.”

“If a neutral trait is pleiotropically linked to an advantageous one, it may emerge because of a process of natural selection. It was selected, but this doesn’t mean that it is an adaptation. The reason is that although it was selected, there was no selection for that trait.”

“That an individual selection explanation is possible doesn’t show that it is true. [...] One needs to carefully distinguish a possible effect of an evolutionary process (group benefit) from one of its possible causes (group selection).”

E. Sober, The Nature of Selection, rozdz. 8, s. 282 (PDF: 290). “Thus correlation isn’t sufficient for causation. [...] So correlation isn’t necessary for causation.”

E. Sober, The Philosophy of Evolutionary Theory, rozdz. 1, §1.1, s. 1 (PDF: 21). “Universal Common Ancestry: All the organisms now on earth descended from a single common ancestor. This thesis does not mean that life evolved from non-living materials only once. Universal common ancestry is compatible with numerous start-ups.”

“In fact, the observed features of fossils, by themselves, don’t entail that evolution has occurred. However, universal common ancestry plus the fact that current organisms differ in their inherited traits suffices for evolution to have occurred. Fossils are icing on the cake.”

E. Sober, The Philosophy of Evolutionary Theory, rozdz. 1, §1.4, s. 6 (PDF: 26). “There is no such thing as the one and only phenotype that “tends” to evolve when there is natural selection. [...] Natural selection is opportunistic. Which traits are fitter than which others almost always depends on accidental features of the environment. The opportunism of evolution by natural selection contrasts starkly with the idea that evolution is pre-programmed.”

“Artificial selection involves conscious choosing; natural selection, in contrast, can be mindless. [...] The weather is not a conscious agent.”

“Mutations are random: Mutations have their causes, but they do not occur because they would be useful to the organisms in which they occur.”

E. Sober, The Philosophy of Evolutionary Theory, rozdz. 4, §4.3, s. 81 (PDF: 101). “Observation O favors hypothesis H1 over hypothesis H2 if and only if Pr(O | H1) > Pr(O | H2). [...] The degree to which O favors H1 over H2 is given by the likelihood ratio Pr(O | H1) / Pr(O | H2).”

“Your observations don’t guarantee that H1 is true and that H2 is false. In fact, they don’t even guarantee that H1 is more probable than H2.”

E. Sober, The Philosophy of Evolutionary Theory, rozdz. 4, §4.3, s. 82 (PDF: 102). “Your observations don’t guarantee that H1 is true and that H2 is false. In fact, they don’t even guarantee that H1 is more probable than H2.”