Short Answer Questions (submit online)

1. Give an example of a claim that was once regarded as scientific but later were not, and of a claim that was once regarded as unscientific but later was not.
2. Compare the syntactic to the semantic view of theories.
3. Describe the mechanisms view of theory and a difficulty with it.

For Further Discussion

• Necessary or sufficient for scientific theories? Many fields claim to be a science, and many of these claims are questionable. Remind yourself of the table of questionable science.
  
  

  Topic	Central claim	Comment
  Astrology	Distant astronomical events can have a causal influence on human well-being	Unsubstantiated by experiment and falsified by the central results of modern astronomy.
  Perpetual motion	Work can be produced without inputing any energy.	Periodically claimed to have been found and always debunked; violates law of local conservation of energy.
  Extrasensory perception (ESP)	Human perception of empirical information independently of any senses (sight, hearing, touch, smell, taste).	No known mechanism, blind case-studies repeatedly shown to fail.
  Vitalistic chiropractors	Body malfunction and disease is caused by imbalance in spinal "emergy" and "subluxations."	Causal claims not taken seriously in modern medicine or science.
  Crystal healing	Crystals placed on parts of the body can cause improvements in human well-being	No peer-reviewed evidence has ever supported this practice.

  • Structure of only science? Can any of these be expressed as theories according to the syntactic view? The semantic view? The mechanisms view?
  • Structure of every science? Many theories are more widely considered to be scientific and apply to a similar domain to some examples in the table above. Can all such mainstream scientific theories be captured by the syntactic view? By the semantic view? By the mechanisms view?
  • Natural domains? To what scientific theories does the mechanisms view apply most naturally? Where does the syntactic view apply most naturally? The semantic view?
• The syntactic view. What are the difficulties of the syntactic view? How can they be overcome?
• The semantic view. A difficulty with the semantic view is how to define "model." To answer this challenge, some proponents of the semantic view argued that one could start with a set of propositions, and then call something a "model" just in case it provided a truth assignment to each proposition.
  • Is this definition sufficiently flexible to describe science?
  • Is it any better than the syntactic view of theories?
  • Can you think of a superior, alternative definition of "model"?
• Thinking about mechanisms. Mechanisms are also difficult to define precisely. Do you see this as a serious problem? How can Craver's original definition be more precise?