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Presentation on Ch. 25: A Retrospective

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by Joseph Stratmann on 1 May 2013

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Transcript of Presentation on Ch. 25: A Retrospective

photo credit Nasa / Goddard Space Flight Center / Reto Stöckli The Epistemology and Methodology of Physics Rationalism and Empiricism Rationalism and the axiomatic model
Start with self-evident "first principles"
Arrive at valid conclusions about nature via logical deduction
Ex: Aristotle
Empiricism and the inductive model
Start with specific observations, generalize outward
Hume's problem of induction
Ex: Bacon
Rationalism and Empiricism as dispositions The Hypothetico-Deductive Model and Falsificationism Der Wiener Kreis contra Poincaré Logical Positivism: All meaningful propositions are capable of verification
Metaphysical propositions are meaningless
Observation sentences are ultimately what verify a theory (Schlick)
Poincaré's conventionalism: Principles of science are creations of the human mind
Neither true nor false, but useful in organizing experience
Ex: Euclidean and non-Euclidean geometry
Einstein and Poincaré Quine's Coherentism
Quine's coherentism: accepted statements form an interconnected whole (a "web of belief"), and the truth of those statements depend on one another
An experience contrary to our theory either means we have to revise a part of our theory, or change the significance of the experience
The truth value of statements are revisable by changing other statements
Ex: Copenhagen Interpretation and Determinism
Physical objects are mere "cultural posits," in the sense that they are "a device for working a manageable structure into the flux of experience."
Theory (e.g. science, math) is undeterdetermined by experience (Quine-Duhem thesis)
Beyond being coherent with experience, the guiding criteria of theory should be simplicity of laws Cushing's Eclectic Three-Tiered View (1) Practice: Facts, laws, theories, and experimental work
(2) Methodology: Rules by which one judges scientific theories
Includes rules of inference, logical structure, and other criteria
(3) Goals of Science: Truth
None of these layers are immune from revision
Changes in outer layer result in changes in inner layer Discussion Questions (1) Should we abandon the rationalist/empiricist divide as being too simplistic in light of the eclectic approaches of most scientists?
(2) How might one modify falsificationism to account for how scientists actually treat falsifying experimental results?
(3) How important is metaphysics to science?
(4) In what sense does science rely on creativity? How does creativity interact with theory and experimental data?
(5) Are there unrevisable statements in science?
(6) Can we construct a theory of scientific knowledge a priori, or to what extent does scientific practice itself dictate our epistemology? Physics and What There Is Einstein's Philosophy of Science The Role of Intuition Alternative #2: Realism about Quantum Mechanics Einstein on Quantum Mechanics and the Goals of Science Science and the Ideal of Truth Alternative #1: Formalism without a Fixed Ontology Hypothetico-deductive model: start with a set of hypotheses, deduce consequences from them
Accuracy judged in terms of correct predictions
Proof vs Warrant
Ex: Newton
Falsificationism: Scientific theories are to be rejected if they have been falsified
To falsify a theory, falsify a prediction it makes
Counter Ex: Kaufmann experiments
Refining falsifiability Discussion Questions Physics as the Fundamental Science Interpreting the History of Physics "Einstein's general position on foundational questions in physics...can be seen as a search for the rational structure of the external physical world that the physicist tries to capture in a causal space-time theory." (285)
Role of creativity
Beyond the observed phenomena, the structure of science includes "the free inventions of the human mind."
Einstein as realist?
There are criteria of judging theories beyond conforming to empirical data:
Simplicity
Fewest premises
Elegance/Beauty
Preservation of intuition in an objective, deterministc world
Dispute over QM: objective/subjective divide
Truth-conducive criteria?
Einstein's reaction to confirmation of general relativity What is an intuition?
Intuition as disposition for belief
Are intuitions universal?
Preserving the phenomena
Grounding of intuitions
Pragmatic?
Axiomatic?
Influence of Kant, far stronger sense
Thought experiments as Intuition pumps
Value in scientific discourse
How do we treat conflicting intuitions?
Role in realist/instrumentalist debate
Interpreting QM
"Fuzzy" criteria for judging theories beyond empirical and logical constraints
Simplicity
Agreement in the community of scientists
Elegance "The object of science is to coordinate our sense experiences and to fit them into a logical system to produce a unity in our world picture and to do this on the basis of the fewest premises possible." (361)
Einstein's problems with a realist interpretation of QM:
(1) Incompleteness
Separability
(2) Undermining of intuitions
Determinism: "God does not play dice"
Simplicity and Elegance Pessimistic Meta-Induction
Science as a history of fruitful failures
At what point do we admit things into our ontology?
The Quinean picture: When a thing becomes indispensible to our best theory, and we can't paraphrase it
Ex: Physical objects
Ex: Quine-Putnam Indispensability Argument
The revisiable nature of indispensibility
A more optimistic, realist reading of the history of physics
Paradigm shifts bring us closer to truths that correspond to the way the world actually is
Controversial positions become banal truths
Ex: Geocentrism vs Heliocentrism
Historical contingency? "An antirealist begins his argument in the microrealm, extrapolates to the macrorealm of everyday experience and leaves the ensuing conundrum at the doorstep of the realist." (348)
Must we accept the antirealist's position concerning the microrealm?
Accounting for intuitions of determinism
Quantum decoherence
Paraphrasing the determinist's claims into the indeterminist language Schrödinger argued that the formalism of QM could translate into either the interpretative language of indeterminism or determinism
The interpretation we choose is based on:
Pragmatic reasons
Simplicity
This theory only works if the de Broglie-Bohm interpretation and the Copenhagen interpretation are empirically indistinguishable
Other problems:
(1) Is explanation essential to a scientific theory?
(2) Is there more than one accurate way to describe reality?
Natural Kinds According to Schrödinger, QM can ground chemistry, which in turn can ground biology
The quantum mechanical formulas for even a water molecule exhibit "hopeless complexity"
In some sense, there is a causal dependence of the other sciences on physics
Is it possible, in principle, for the other natural sciences to be completely replaced by physics?
Does QM overturn the drive towards reduction in some ways within physics?
Maudlin quote: "In qunatum theory, then, the physical state of a complex whole cannot always be reduced to those of its parts, or to those of its parts together with their spatiotemporal relations...The result of the most intensive scientific investigations in history is a theory that contains an ineliminable holism."
In what sense is the drive towards reductionism an intrinsic part of physics? (1) To what extent should we appeal to intuition when deciding between two different theories?
(2) If intuitions are merely useful (i.e. motivate us to critically reevaluate an existing theory), can't we achieve the same effect by simply maintaining a generally critical disposition?
(3) To what extent are intuitions subject to revision within one's accepted body of statements?
(4) Was Einstein justified (but not necessarily right) in resisting the Copenhagen Interpretation for the reasons he did?
(5) Is it possible to keep formalism and interpretation separate, or is the formalism already laced with theory?
(6) Can the indeterminist account for the determinist's intuitions or not? "Monod believes that we have a biological or genetic need (as the result of evolution) for the all-encompassing explanations provided by animist theories. Science cannot yield these since its knowledge is always provisional, rather than being based on or guaranteed by absolute first principles."
Animist theory - Posits a universal telenomic principle (teleology)
Conflict between science and psychological needs
Love-hate relationship
Rorty on truth
Science deals with justification, not truth
Justification is relative to a particular audience (e.g. a scientific community)
In what sense does "the Truth" relate to scientific practice?
Is belief in "the Truth" itself pragmatically justified?
It seems like we are still left with a deeply fractured horizon in the debates we have looked at
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