Teleology Naturalized

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Section 3.7

• Teleology Naturalized

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Questions

• What is teleology?
• Why are we striving to escape from it?
• What are the remnants of teleology in biology?
• What are the possible explanations of biological
  teleology?
• How can we naturalize biological teleology?

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What is teleology?

• Teleology is a form of explanation
• Teleology explains phenomena by referring to
  purposes, ends, aims, etc.
• Teleology is an answer to why? and what for?
  questions
• Why do birds have wings?
• Why do we have eyes?
• What are cell phones for?

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What is teleology?

• Teleological explanations versus mechanical
  explanations
• Q Why does rain fall?
• M Rain falls because evaporized water condenses
  when temperature decreases and its density
  increases. Hence, the gravitational force over
  water drops exceeds ascending force of air.
• T Rain falls in order to water crops and nourish
  living things.

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What is teleology?

• Some historical preliminaries of teleological
  explanations
• Plato Everything was created by demiurgos. Since
  demiurgos (god) created everything for a reason,
  everything is at its best
• This ordered world is of mixed birth it is the
  offspring of a union of Necessity and Intellect.
  Intellect prevailed over Necessity by persuading
  it to direct most of the things that come to be
  toward what is best, and the result of this
  subjugation of Necessity to wise persuasion was
  the initial formation of this universe (Timaeus,
  48a trans by Zeyl).

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What is teleology?

• Aristotles teleology
• Like moves to like For instance, a stone falls
  toward the center of earth because they are both
  made up of same essential ingredients.
• Development of organisms from birth to adulthood
  is guided by an intrinsic purpose. The adult
  organism is the purpose of development.
• Functional parts of organisms exist because of
  their benefits to their possessors.
• Pure chance can not explain the order we observe
  in organic and inorganic worlds.

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Why are we striving to escape from teleology?

• Findings of the sciences eliminated teleological
  explanations from many fields of science
• Newtonian physics explains movements of objects
  without referring to purposes
• There is no purpose of a stone which falls down
  to earth. It just obeys a law of nature.
• Nature is not perfectly ordered. For instance,
  planets do not follow circular orbits as once
  imagined by ancient Greeks.
• Earth is not the center of the universe. Hence,
  the universe is not centered around humans.

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What are the remnants of teleology in biology?

• Functions and functional explanation
• Functional explanation is a remnant of
  teleological talk because by assigning functions
  to objects we answer a what for question.
• For instance What is the function of DVDs? can
  be translated as What are DVDs for?
• In the case of artifacts, there seems to be no
  interesting problem. Artifacts are produced or
  used for specific purposes DVDs are produced
  and used for storing digital information.

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What are the remnants of teleology in biology?

• What about biological traits?
• What is an hemoglobin molecule for? Is this
  question a legitimate one? Can you sense any
  problem about this question?
• The problem is that hemoglobin molecules are not
  designed by intelligent agents like humans.
• When we say that the function of hemoglobin
  molecules is to carry oxygen to tissues we must
  be meaning something else.

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What are the possible explanations of biological
teleology?

• Creationist Explanation
• An omnipotent God created all living things at
  once. Since living things are products of an
  intelligent being, functions they possess reflect
  Gods intentions.
• In other words, we must analyze living things
  just as we analyze artifacts. What for?
  questions are legitimate questions.
• For instance What is hemoglobin for? can be
  answered by the statement It was designed by God
  to carry oxygen to tissues.

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What are the possible explanations of biological
teleology?

• What is wrong with the creationist approach?
• If we are to explain complexity and order in
  nature, we should do it by using simpler means.
  Even if we solve the problem of explaining
  natural order, we need to explain how God
  achieved his aims. The concept of God needs
  explanation too.
• Organic world is full of imperfect adaptations.
• We can observe the change in the living world
  even in our lifetimes. Think of the evolution of
  HIV in a few decades.

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What are the possible explanations of biological
teleology?

• Darwinian Explanation
• Functional traits of organisms are products of a
  lengthy chain of natural events. The totality of
  these natural events is called natural selection.
  
• What is natural selection?
• Organisms in a population may have different
  traits Birds have differing wing lengths,
  bacteria have differing capacities of antibiotic
  resistance, humans have different eye colors,
  etc.

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Darwinian Explanation

• What is natural selection?
• Some of these differences are heritable. For
  instance, resistant bacteria have resistant
  offspring, tall parents have tall children, etc.
• These heritable differences affect reproduction
  rates of their owners. For instance, resistant
  bacteria produce more offspring, tall parents
  produce greater a number of children, long winged
  birds have more offspring, etc.

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Darwinian Explanation

• What is natural selection?
• Having more offspring changes the composition of
  the population in favor of fitter organisms. The
  fitter trait increases in the population.
• The function of a trait is the effect which
  helped the trait to spread The function of
  hemoglobin is binding oxygen because binding
  oxygen is the effect which caused the spread of
  hemoglobin carrying organisms.

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Darwinian Explanation

• Some conceptual distinctions
• Adaptations versus adaptive traits Adaptation
  refers to a product of natural selection. A
  product of natural selection may or may not have
  current utility. An adaptive trait is currently
  beneficial to the organism.
• For instance hemoglobin binds CO with a greater
  affinity than it binds to oxygen. CO is a toxic
  agent. In some circumstances, having hemoglobin
  may be detrimental to the organism. But it is
  still an adaptation.
• Adaptation is an historical concept, whereas
  adaptiveness is not.

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Darwinian Explanation

• Some conceptual distinctions
• Ontogenetic adaptation versus phylogenetic
  adaptation
• Ontogenetic adaptation Adaptive changes that
  occur during the lifetime of an organism. For
  instance, a human infants learning how to deal
  with physical objects is an ontogenetic
  adaptation.
• Phylogenetic adaptation Adaptive changes that
  occur during the genesis of a species. For
  instance, the growth in brain size of primate
  lineage resulting in humans is a phylogenetic
  adaptation process.

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How can we naturalize biological teleology?

• Etiological theories of function
• Proponents of etiological theories claim that
  functional explanations anwer the question why
  is trait x present?
• Etiological theories try to demarcate accidental
  effects from genuine functions. For instance,
  hearts make thumping noises besides pumping
  blood. We dont want to ascribe functions to such
  accidental effects. But we need a ground to
  distinguish functions from side-effects.
• The ground for that distinction is provided by
  designer and user intentions in the case of
  artifacts. For instance when we ask what is the
  function of that fan in my computer? we are
  asking why did the engineer put that fan in that
  specific location.

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How can we naturalize biological teleology?

• Etiological theories of function
• In the case of organic functions we explain the
  presence of the trait by referring to a specific
  effect that led to the selection of the trait.
• For instance the function of hearts is to pump
  blood can be justified by the statement the
  effect that lead to the spread of hearts in an
  ancestral population was their ability to pump
  blood.
• This way, we may demarcate functions from
  accidental effects Making thumping noises is not
  a function of hearts because hearts are not
  selected for that effect.

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How can we naturalize biological teleology?

• Causal-role theories of function
• Function ascriptions do not need to be historical
  hypotheses.
• The aim of function ascription is to analyze
  complex systems into simpler parts.
• Functionthe contribution of simpler parts to a
  systemic capacity.
• For example, when we ask what is the function of
  that fan in my computer? we are in fact asking
  what contribution does that fan make to the
  working of that computer

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How can we naturalize biological teleology?

• Causal-role theories of function
• Flowchart diagrams, abstract descriptions of
  electronic circuits or assembly lines are best
  examples of this approach. Consider the computer
  fan example I mentioned before. The function of
  the fan is to cool the processor. Cooling the
  processor is a capacity of the computer which is
  achieved by the inner workings of the fan. The
  fan can be decomposed into its simpler parts.
  These simpler parts contribute to the cooling
  capacity of the fan, hence, one can explain how
  the cooling capacity of the computer is realized
  by means of analyzing relevant parts into simpler
  and simpler capacities they have.