Related Experiment Video
Updated: May 23, 2026
14:29
Examination of Thymic Positive and Negative Selection by Flow Cytometry
Published on: October 8, 2012
The negative view of natural selection.
1Department of History and Philosophy of Science, University of Cambridge, Free School Lane, Cambridge CB2 3RH, UK. jgb37@cam.ac.uk
Summary
This study challenges the argument that natural selection cannot explain individual traits. It demonstrates that natural selection is relevant to explaining organismal traits using a refined criterion for explanatory relevance.
Area of Science:
- Philosophy of Science
- Evolutionary Biology
Background:
- The Sober-Walsh-Pust argument posits that natural selection cannot explain individual organism traits.
- This argument links the explanatory power of natural selection to metaphysical concepts like origin essentialism.
Purpose of the Study:
- To critically evaluate the Sober-Walsh-Pust argument against natural selection's explanatory role for individual traits.
- To propose and defend a more robust criterion for explanatory relevance in evolutionary biology.
Main Methods:
- Analysis of the counterfactual criterion used in the Sober-Walsh-Pust argument.
- Application of Michael Strevens' criterion of explanatory relevance to the case of natural selection.
Main Results:
- The Sober-Walsh-Pust argument is shown to rely on a flawed counterfactual criterion for explanatory relevance.
- A more defensible criterion for explanatory relevance supports the view that natural selection explains individual traits.
Conclusions:
- The explanatory scope of natural selection is not dependent on origin essentialism.
- Natural selection remains a relevant explanatory factor for the traits of individual organisms.
Related Concept Videos
01:32What is Natural Selection?
Natural selection is an evolutionary process in which individuals with survival-promoting traits reproduce at higher rates. These favorable traits become more common within a population or species. Naturally selected traits initially arise via random genetic mutations. In order for selection to occur, there must be variation within a population, the trait controlling the variation must be heritable, and there must be an evolutionary advantage for variation in the trait.
01:38Limits to Natural Selection
Organisms that are well-adapted to their environment are more likely to survive and reproduce. However, natural selection does not lead to perfectly adapted organisms. Several factors constrain natural selection.
01:21Frequency-dependent Selection
When the fitness of a trait is influenced by how common it is (i.e., its frequency) relative to different traits within a population, this is referred to as frequency-dependent selection. Frequency-dependent selection may occur between species or within a single species. This type of selection can either be positive—with more common phenotypes having higher fitness—or negative, with rarer phenotypes conferring increased fitness.
01:46Types of Selection
Natural selection influences the frequencies of particular alleles and phenotypes within populations in several different ways. Primarily, natural selection can be directional, stabilizing, or disruptive. Directional selection favors one extreme trait and shifts the population towards that phenotype while selecting against individuals displaying alternate traits. Stabilizing selection favors an intermediate trait with a narrow range of variation. Deviation from the optimal phenotype towards an...
01:15Natural Selection and Adaptation
Natural selection, a fundamental concept in evolutionary biology, is the mechanism by which evolution is driven, favoring organisms that are best adapted to their environments. This process enhances their chances of survival and reproduction. Adaptation, a key outcome of this process, involves genetic modifications that optimize an organism's functionality under specific environmental challenges, such as extreme cold or thinner air at high altitudes.
Beyond physical adaptations, psychological...
Beyond physical adaptations, psychological...
01:23Criticisms of the Evolutionary Perspective
In a study where individuals posing as strangers offered compliments and proposed casual sex to students, the responses differed significantly based on gender. Not a single woman accepted the proposal, while 70% of the men agreed. This outcome provides a useful scenario to explore through the lens of evolutionary psychology and social learning theory, highlighting the diverse perspectives on human sexual behaviors.
Evolutionary psychology provides one explanation for these findings, suggesting...
Evolutionary psychology provides one explanation for these findings, suggesting...