Science News
Science (?) News
Demarcation
“We [scientists] believe that the world is knowable,
that there are simple rules governing the behavior
of matter and evolution of the universe … [and]
that the collection of these truths is what we call
physical science. Any intelligent alien anywhere
would have come upon the same logical system
as we have to explain the structure of protons and
the nature of supernovae.
“This statement I cannot prove. This statement I
cannot justify. This is my faith.”
Sheldon Glashow, Nobel Laureate Physics, Harvard
The commitments of Glashow’s credo:
Epistemological: the world is knowable and the
physical sciences have a lot of this knowledge
 Simplicity: there are simple rules governing the
behavior of matter and evolution of the universe
 Realism and, thus, intersubjectivity: any
intelligent alien anywhere would have come upon
the same logical system as we have to explain the
structure of protons and the nature of supernovae.
 Fallibilism: This statement I cannot prove. This
statement I cannot justify. This is my faith.

Commitments displayed in
The Elegant Universe

Epistemological:
If a theory (such as String Theory) isn’t testable, then
no one should believe/accept it whatever its other
merits.
If String Theory isn’t testable (e.g., strings by
hypothesis can not and will not be observed), one
needs to worry if it is science or, rather, philosophy –
that is, metaphysics in Ayer’s sense.

Quasi (at least) Metaphysical:
There is “a theory of everything,, even if we don’t yet
know what it is, and it is simple and elegant.
Commitments displayed in
The Elegant Universe

Aesthetic/theoretical/epistemological and/or
metaphysical:
Simplicity
Elegance
Unification
 Unifying
Quantum Theory and Relativity
 The physics of the very small and the big (including the very
big)
 Indeterminacy (at the quantum level) and Determinacy at the
macroscopic level
Demarcation
A.J. Ayer:
 Logical Positivism (Logical Empiricism)
 Distinguishing science from non-science
(including metaphysics) and from pseudo-science
 At its core: logic and empiricism
 Arguing for the positive difference science can
make in the world.
 Seeking to expose what makes non- or pseudoscience just that.

Demarcation

The target: (A particular form of) Metaphysics
 Any effort to discover a “transcendent reality” or any claim to
have discovered aspects of such a realty
 Transcendent reality: A reality that transcends (goes beyond,
hides behind…) the world of science and common sense.


Verifiability: Scientific claims and theories, unlike nonscientific claims and theories (e.g., metaphysical claims)
can be verified (shown to be true) through observation.
A sentence is factually significant (meaningful) … if,
and only if, there are observations that would lead one
to accept that sentence as true – or reject it as being
false.
Demarcation
A sentence is factually significant (meaningful)
… if, and only if, there are observations that
would lead one to accept that sentence as true –
or reject it as being false.
 If, alternatively, the truth or falsity of a
sentence is consistent with any and all future
observations, it is a pseudo sentence or claim.
 What of kinds of sentence (say, ethical, or a line
of poetry or of a novel) that don’t meet this
criterion but also don’t claim to be scientific. Are
they “meaningless”?

Demarcation
What about sentences (say, ethical such as
‘Murder is wrong’, or a line of poetry or of a
novel) that don’t meet this criterion but also don’t
claim to be scientific. Are they “meaningless”?
 Literally, yes. Though they may carry emotional
meaning for an individual, they lack factual
significance.
 They do not constitute a claim about a matter of
fact.

Demarcation

Fine-tuning the criterion and argument for it
The distinction between “practical verifiability”
and “verifiability in principle”
Some sentences are practically verifiable; we can
undertake the observations that demonstrate their
truth.
Some sentences cannot be verified practically (or
we do not feel the need to attempt to verify them)
but are ‘verifiable’ in principle: Simply because we
lack the physical capacity or technical means to do
so (that red school house…). Yet we do know what
observations of matters of fact would verify them.
Demarcation
Fine-tuning the criterion and argument for it
 Understanding ‘to verify’ as to establish or
discover the truth of a sentence, we need to
decide between ‘strong’ or conclusive
verifiability, and a ‘weaker’ sense.
 Conclusive verifiability would call for too
much, ruling out the laws and generalizations
so important to science that yield an infinite
number of observational predictions as
anything more than “nonsense,” albeit
“important nonsense”.

Demarcation
But as such statements are important features
of science (if not basic to science), ruling them
out as “nonsense” is wrongheaded.
 Better to adopt a more reasonable but still
clear criterion involving verifiability:
 Namely, a sentence or claim of any sort is
genuine only if it is verifiable, and it is
verifiable if it possible for
observations/experience to render it probable.

And now, as Monty Python would say,
for something completely different (?)
(Sir) Karl Popper
 Science the autumn of 1919, wrestling with the
question “Is there a criterion for the scientific
character or status of a theory?”
 Distinct from the question “When is a theory
true or acceptable?”
 Alternatively put, what distinguishes a
genuinely empirical method and a non- or
pseudo empirical method?

Popper’s Falsifiability
Comparing 4 then popular and much discussed
theories: Relativity, Marxism, Freudianism,
and Adlerian Psychology
 Although each of the latter three might contain
important truths or insights, and although they
are said to enjoy extensive confirmations
(supporting observations and experiences),
they turn out not to be scientific.
 Although it was unclear at the time whether
Einstein’s theory was true, it turns out to be
scientific.

Popper’s Falsifiability
The criterion used to make these judgments
and to be generalized: Falsifiability
 Every genuinely scientific theory is a
prohibition. It forbids certain things to happen.
 A theory that is not falsifiable (refutable) by
any conceivable event is not scientific.
 Relativity does prohibit or forbid certain things
to happen. Moreover its predictions are “bold”
and “risky”. And 1919 brought about the first
important confirmation of it.

Popper’s Falsifiability
The criterion used to make these judgments
and to be generalized: Falsifiability
 So what is wrong with the other three?

After all, Popper concedes they enjoy numerous
confirmations (or verifications in Ayer’s terms).
But Popper also maintains that numerous
confirmations should not count unless they are bold
and risky.
For Popper, none of the three is falsifiable.
 But what does this mean?

Popper’s Falsifiability
The criterion used to make these judgments
and to be generalized: Falsifiability
 For Popper, none of the three is falsifiable.
 But what does this mean?
 Two (exclusive?) senses:

Each theory is compatible with any and all relevant
observations, events, experiences, etc.
Advocates of each theory see confirmations
everywhere and explain away apparent counterexamples.
Similarities and Differences
Shared interest in demarcation criterion
 Emphasis on matters of fact, observations,
experience…
 Emphasis on evidential relations as logical.
 The difference:

Ayer emphasizing the importance of confirmation
or verification
Popper drawing on the fact that while a
generalization can never be proven (conclusively
verified), it can be falsified.