Philosophy of Biology
Natural Selection vs Intelligent Design
- Watch maker argument
- Designer is a more plausible explanation than randomness for the creation of complex system.
- What's wrong with intelligent design?
- Not testable
- Popper's falsifiability criterion
- Can't deal with probability statements
- Test against one or more competing hypotheses
- Physical theories do not make testable predictions without auxiliary propositions
- Auxiliary propositions must be independently supported
- No auxiliary propositions about designer's goal and abilities
- ID always have a way out by pushing back in time to a mindless state until the big bang.
- Observation in Popper's concept of falsifiability.
- ID cannot make predictions.
- Refute evolutionary cannot irreducibly complex adaptations does not imply proving of ID.
- Evolution does not guarantee stepwise accumulation. No 1,2,3 legs horses.
Gould, The Spandrels of San Marco
- Adaptation explain everything in natural selection with speculative tales
- Fail to consider alternative to adaptive stories
- Adaptationist programme
- An organism is atomized into traits and these traits are explained as structures optimally designed by natural selection for their functions
- After the failure of part-by-part optimization, interaction is acknowledged via the dictum that an organism cannot optimize each without trade-offs
- Trivialize genetic drift, allometry and other non-adaptive evolution.
- Common style of arguments
- If one adaptive argument fails, try another one
- If one adpative argument fails, assume that another must exists
- If the the absence of a good adaptive argument in the first place, attribute failure to imperfect understanding of where an organism lives and what it does
- Emphasize immediate utility and exclude other attributes of form
- Spandrels of Cathedral
- Generate for other purpose then adopted the current function.
- Alternatives to adaptationist programme
- No adaptation and no selection at all. Pure random factors.
- No adaptation and no selection on the part at issue; form of the part is correlated consequence of selection elsewhere.
- Decouple selection and adaptation
- Adaptation and selection but no selective bias for differences among adaptations.
- Adaptation and selection, but the adaptation is a secondary utilization of parts present for reasons of architecture, development or history
- Evolutionary constraints
- Phyletic constraints, no flying molluscs, no elephant size insect
- Developmental constraints, early stage strongly restrictive of later development.
- Two definitions of adaptation
- A feature is an adaptation only if it was built by natural selection for the function it now performs
- Feature that enhances current fitness, regardless of its historical origin
- any feature that promotes fitness and was built by selection for its current role as a function
- operation of a useful character not built by selection for its current role as an effect
- Significance of exaptation
- A solution to the problem of preadaptation
- Primary exaptations and secondary adaptations
- The sources of exaptation
Natural selection, positive vs negative theory
- negative theory of natural selection
- random mutation
- natural selection did not create the tree of life, it just determine which branches were removed and which remained
- Cumulative selection
- Population change
Type vs token
- Scare resource