To save the phenomena: constructive empiricism

1
To save the phenomena constructive empiricism

• The belief involved in accepting a scientific
  theory is only that it saves the phenomena,
  that is that it correctly describes what is
  observable
• (van Fraassen,185-186)

2
Term paper and final exam

• Final exam is scheduled for Thursday April 19, 6
  pm in SBE 1220
• Term paper is due March 22nd. Hard copy to me and
  electronic copy to Turnitin.com. Note the proviso
  in penalty for late submissions however
• Please set up your account at Turnitin.com and
  familiarize yourself with the site before the due
  date.
• Remember you are presenting an argument in
  support of a conclusion in your paper. You cannot
  just string together quotes!

3
Steps leading to constructive empiricism

• What is the argument used by anti-realists to
  motivate our acceptance of their position?
• Strong underdetermination
• For every theory there exist an infinite number
  of strongly empirically equivalent but
  incompatible rival theories
• If two theories are strongly empirically
  equivalent then they are evidentially equivalent
• No evidence can ever support a unique theory more
  than its strongly empirically equivalent rivals
• Therefore, theory-choice is radically
  underdetermnined.

4
Steps leading to constructive empiricism

• Focus on the second premise If two theories are
  strongly empirically equivalent then they are
  evidentially equivalent
• Distinguish between empirical and evidential
  equivalence
• Theory choice involves non-empirical features.
  E.g. Kinetic theory of motion

5
Steps leading to constructive empiricism

• What is the constructive empiricists response to
  the challenge?
• The underdetermination is resolved by pragmatic
  considerations, not epistemological ones

6
The difference between Scientific realism and
Constructive Empiricism

• Scientific realism science aims to give us a
  literally true story of what the world is like
  and acceptance of a scientific theory involves
  the belief that it is true (van Fraassen cited
  on 185)

• Constructive empiricism science aims to give us
  theories which are empirically adequate, and
  acceptance of a theory involves belief only
  that it is empirically adequate (ibid)

7
Difference between scientific realism and
constructive empiricism

• The realist thinks science aims at truth with
  respect to unobservable processes and entities
  that explain observable phenomena

• The constructive empiricist thinks that science
  aims to tell the truth about what is observable
  and rejects the demand for explanation for all
  regularities in what we observe they are
  agnostic with respect to unobservables

8
The realist fights back defending scientific
realism against constructive empiricism

1. Challenge the observable/unobservable distinction
2. Acceptance of theory involves a commitment to
   interpret and talk about the world in its terms
3. The strong form of the underdetermination
   argument applies to both unobservables and
   observables. The constructive empiricist is
   guilty of selective skepticism. The constructive
   empiricist is being inconsistent.

9
First objection observable/unobservable

• First objection no meaningful distinction can be
  drawn between the observable and the
  unobservable. Furthermore, no epistemological
  significance hangs on the distinction.
• The realists point is that there is nothing
  special about unobservable entities that prevents
  us knowing about their existence. That is,
  nothing is unobservable in principle (Ladyman
  188).
• This point was raised by Grover Maxwell in 1962.

10
Observable/unobservable distinction

• Maxwell there is a continuum between seeing
  normally, seeing with binoculars, seeing with a
  microscope, seeing with an electron microscope.
  Where is the line between observable and
  unobservable?
• van Frassen vague predicates, like red,
  tall, can do epistemological work.
• van Frassen what we can and cannot know
  coincides with the observable and unobservable.

11
Reply to the first objection

• van Fraassens aim skepticism about
  unobservable.
• Maxwell nothing is unobservable in principle.
  This means that entities may be observed under
  the right sort of circumstances. Electron
  microscope, for example.
• For van Frassen, observable is to be understood
  as observable-to-us X is observable if there
  are circumstances which are such that, if X is
  present to us under those circumstances, then we
  observe it (188).

12
Reply to the first objection

• What we can or cannot observe is due to the fact
  the human organism is, from the point of view of
  physics, a certain kind of measuring apparatus.
  As such it has certain limitations it is these
  limitations to which the able in observable
  refersour limitations qua human beings (189)

13
Reply to the first objection

• The us refers to the human epistemic community.
  The epistemology is our epistemology
• However, if in the future, we encounter other
  beings whose senses are better than ours, and the
  two epistemic communities are integrated, then
  the observable/unobservable boundary shifts
  appropriately. We would be at the sight-impaired
  end of the community

14
Reply to the first objection

• What then is the difference between the moons of
  Jupiter and positrons?
• Were we in a space ship and were close enough to
  Jupiter, we would observe the moons of Jupiter.
• However, we do not directly observe positrons. We
  infer their existence by the tracks in a cloud
  chamber.
• There may well be another theory which is
  empirical equivalent but denies that positrons
  existthe leprechaun theory.

15
Reply to the first objection

• The realist may object why does van Frassen
  allow change in spatiotemporal location when
  determining what is observable, but not the
  constitution of our sensory organs?
• van Frassens response we are like beings whose
  only difference is that they are closer to
  Jupiter, but we are not like beings with
  different sensory organs.
• If we had electron microscopic eyes, we might not
  observe positrons.

16
Second Objection Acceptance and belief

• The objection Acceptance of theory involves a
  commitment to interpret and talk about the world
  in its terms
• The scientific realist challenges van Fraassens
  distinction between belief and acceptance the
  realist argues that van Fraassens position is
  incoherent.

17
Second objection

• The difference between belief and acceptance
• Does the following statement I believe p (p be
  any statement) but it is not true, make sense?
• Believing in p implies one is committed to the
  truth of p
• van Frassen claims that I accept p does not
  imply that one is committed to the truth of p.
• Is he right?

18
Reply to second objection

• Does it make sense to say that I accept p but p
  is not true? Is there a contradiction in saying
  I accept p but p is not true?
• Consider the case of Newtonian mechanics
• We accept it for use everyday but we are not
  committed to saying that it is true, which it
  isnt strictly speaking.

19
Belief and acceptance

• The above example illustrates the difference in
  epistemic attitude between believing in and
  accepting a statement, or theory.
• There appears to be no contradiction in accepting
  a theory for use but believe it to be false.
• The realist objection fails.

20
Third objection selective skepticism

• In order to appreciate the third objection, we
  need to consider what realists mean by
  explanation?
• Realists hold that the truth (or approximate
  truth) of a hypothesis is a necessary condition
  for it to be part of a genuine scientific
  explanation.
• That is why, for realists, explanations require
  more than empirical adequacy (what is empirical
  adequacy?)

21
Scientific explanations

• Realists argue that there are principled ways of
  breaking underdetermination. A rational
  justification can be offered.
• For them, inference to the best explanation (IBE)
  shows that empirical equivalence of theories does
  not imply evidential equivalence.
• Realists use IBE to argue for the existence of
  unobservables.
• The constructive empiricist must offer a critique
  of IBE if they are to succeed in arguing their
  case.