Larson 4

Two summaries:

• Evolution becomes scientific, with a mechanism, rather than a vague idea. 
  
• But some pieces to make it all make scientific sense were still missing, particularly genetics and what causes variation
  
• some people responded: this is a great idea, it is exciting to do the research to fill in the missing pieces
• others responded: this can't be true because it can't explain the missing pieces
• others accepted the basic idea but proposed different versions
  

• Many different responses from religion
• by this time some scientists are embracing the idea that supernatural explanations not  needed in science--religious leaders saw this as a threat
• where do humans get their souls worried religious leaders
  
• others believed science showed us more about God through the natural world God created
  

• competition for resources was something England was winning, so the idea was less threatening
  
• social darwinism: survival of the fittest applies to human society (either individual or between nations)
  
• scientists liked the argument that explanations of the natural world should use only natural causes (not supernatural ones including God)
  
• this idea had come in three waves
  
• Mechanical philosophy during the scientific revolution
  
• Enlightenment was a second wave of removing religious explanations from science
• Darwin published as a third wave was building--a reaction against natural theology
  
• Thomas Henry Huxley became a defender of Darwin because Darwin's evolution had no vague organizing forces or divine design
  
• Huxley promoted Darwin's ideas as killing off superstition and as the triumph of materialism
• Origin of Species was widely read and talked about
• Scientists were generally quick to applaud the idea
• evolution explains the relatedness of species that we see and that natural selection provides a mechanism
• but other pieces were missing that were needed to make the theory complete, in particular a theory of inheritance (Mendel's work was not yet known) and an explanation of variation
• over time these missing pieces became more controversial in the scientific community
• until they were solved by the modern synthesis (chapter 10)
  

How does Darwin make the argument in the book?

• starts with the analogy of artificial selection (selective breeding) of domestic animals, such as fancy pigeons:
  

• the natural equivalent is the struggle for existence, leading to natural selection (there is also sexual selection)
• Darwin provided lots of detailed evidence--this is what was convincing to other scientists
  
• are natural selection and the survival of the fittest the same thing? consider the peacock
  
• any natural variation that provides a small advantage will allow animals that have it to have a better chance of surviving and therefore the trait will spread and eventually win out
  
• this selection acts on small inborn variations which Darwin could not explain but which were known because they were the basis of selective breeding (Mendelian genetics and a mechanism for variation were not yet known--these were the key holes in Darwin's theory)
• Darwin didn't reject the possibility that characteristics acquired after birth could be inherited
• Darwin as a follower of Lyell assumed the variations would be tiny, Huxley favored the idea of larger mutations (saltations)
• Darwin ends with the idea that God created the first species--he wanted to make the idea acceptable to his Christian friends and family members, whatever he believed about God's role himself
• Huxley opposed this because he philosophically wanted science to never need to mention God--he wanted the two to be separate
  

Asa Gray, a key American botanist, proposed a theory of theistic evolution

• God creates the variations on which natural selection then works
• Darwin rejected this because natural selection was too cruel a process to be used by a good God
• but it fit Gray's Calvinist religious beliefs (Presbyterians at the time took predestination quite seriously)

Darwin assumed evolution would follow a branching patterns

• if there were ecological niches available one species would differentiate into many--principle of divergence
  
• we don't see evolution because it takes too long, but we see the pattern of related species
• Darwin cannot explain the starting point of life, ends with the thought that God or nature breathed life into the first living things, then evolution took over

Darwin's theory was seen as a threat to religion in a way that Lyell's had not been

• evolution explained the characteristics of species of plants and animals, not clever design by the creator
• many educated people had been willing to give up a literal interpretation of the 6 days of creation, but not seeing God's hand in each species
• Darwin emphasized how natural selection produced plants and animals who could win the competition for survival, not perfect ones or ones that fit our ideas of morality
• Darwin wrote in a letter there is too much misery in the world for it to be the product of design and beneficence
• evolution is random and cruel--do we want a God who works that way
• Darwin had lost a daughter he loved very much and was chronically ill himself--he saw the world as a bleak place
  

Natural Theology was still popular among scientists and could initially be reconciled with Darwin's evolution

Darwin avoided the topic of human evolution in Origin of Species

• This was the other crucial religious issue at the time--did human beings evolve from apes instead of being specially created by God?
• people didn't like losing that special status/where does the soul come in
• Huxley pushed the controversy, why?
  
• Huxley took the issues as an opportunity to exclude religious arguments from science
• language and even altruism might be the product of evolution alone
• he thought sexual selection necessary to explain races--they aren't necessarily better adapted but women picking a mate pick different features in different cultures
• sexual selection: what advantage does a peacock's tail provide?
• much of the data the racist ideas were based on was just wrong
  
• some scientists still believed that God put a soul into a particular ape, specially creating humans
  

Ways of reconciling evolution and Christianity:

• see the 6 days of creation as metaphorical
• see evolution as the mechanism God uses for creation
• see God as creating the laws of nature, which work to make an amazing world
  
• see religion as an authority for matters of faith but not for understanding of the natural world
• see the Bible as deeply true religious ideas but written within a view of the world that we have now outgrown