Transcript Popper On Science

Popper On Science
Economics 201 - Lawlor
What is and inductive inference?
• Example: “All Swans are white”
• Needs an observation to confirm it’s truth.
• It is impossible to think of a logical deductive proof,
one that proceeds from a general principle to a
single instance
• The next observation could always contradict it.
• Economics Example: “Returns to holding
equities are the highest of all classes of
investment”
Problem with induction (pp. 27-30
• According to Hume and Popper
• The is no “logical” way to define an
inference
• Must always be open to disproof
• Is always tentatively held
• Could be disproved by the next
observation
Four Aspect of Theory Testing (p.
32)
• 1.Internal Consistency – math, logic
• 2. Deductive Determination of Testable
Hypotheses
• 3. Comparison with other theories – to
eliminate special cases, more generality,
etc..
• 4. Empirical Testing of conclusions derived
in #2
“Demarcation” of Empirical Science
(pp. 34-36)
• A method of distinguishing what is and is not
empirical science
• First, why do we need one
• To be clear about the problem discussed by
Ludwig Wittgenstein: Can the problem of
“universal statements” about “reality” be reduced
to a logical relationship
– Logical Positivists and early Wittgenstein said “yes,”
“meaningfulness” and the “picture theory”
Popper and Hume’s reply...(pp. 368
• If, with Hume, we recognize the difference
of empirical and a priori statements, and if
we recognize that only a prior truth is
established by deduction…
• Then statements that depend on empirical
verification can never be proven true by
deduction
• Must always remain inductively “tentative”
“Falsifiability” (pp. 40-41)
• A method, or “convention”, of presenting
an inductive, empirical statement, in such
a way as to ensure it is scientific, not
metaphysical (in the sense of not being
determined by evidence)
• Read quote p. 40-1, “But I shall…”
• “it must be possible for an empirical
statement to be refuted by experience”
Status of “Falsification” (pp. 41-42)
• Is itself a not provable by deduction
• We must judge by experience if it is useful
to wisely apply it when conducting science
• Asks: “Is science better off accepting as
proof ‘evidence’ or ‘belief’”?
• When and whether it is the former over the
latter is Popper’s point: Scientific progress
is made when more evidence is explained
Range of empirical “falsifiability is a
mark of its generality
• “Not for nothing do we call the laws of
nature ‘laws’: the more they prohibit the
more they say” (p. 41)
• Consider the “law of gravity” – what sort of
things does it prohibit?
• Consider “the law of diminishing returns” in
the same light
• “prohibits” much less
Scientific Objectivity and Subjective
Conviction (pp. 44-48)
• Belief and Faith have no role in an
empirical science unless it is faith in
evidence
• Evidence as judged by the weight of
evidence by a wide community is Popper’s
ideal currency to a scientific community
• He is calling us to be true empiricists – to
live without conviction, tentatively, based
on evidence
Science and Metaphysics
• Any belief we consider too precious to be
open to “falsification,” is a metaphysical
belief for Popper
• It is difficult to live without “belief”
psychologically – so it is difficult to be a
true empirical scientist
– But such is the ideal science
– And also his description of how science progresses
» Note not by “ideology” but by “facts”
Note that this was not just
philosophy for Popper
• Jewish refugee from Vienna, 1932
• Author of The Open Society and Its
Enemies
• He personally lived through the domination
of German public discourse by the Nazi
ideology, and suffered from it
• Proposed that public debate, to guard
against this, be based on “facts,” not
“belief”