Phil 3318: Philosophy of Phil 3318: Philosophy of ScienceScience

McDaniel CollegeFall 2004BMC 110

TTh 10:00-11:30

‘‘The’ Scientific MethodThe’ Scientific Method

• How do we know that we know?

Groundhogs don’t climb trees.

The planets move in elliptical orbits.

The universe is made up of 11-dimensional strings vibrating at

different frequencies.We can remember 7 digits plus or

minus 2.There are at least two fundamentally different kinds of memory: declarative and procedural.

How to investigate?How to investigate?• Groundhogs don’t climb trees

• The planets move in elliptical orbits

• The universe is made up of 11-dimensional strings vibrating at different frequencies

• We can remember 7 digits plus or minus 2

• There are at least two fundamentally different kinds of memory: declarative and procedural.

Naturalistic Observation

Prediction and Observation

Mathematics / Unity / Occam’s razor

Experimentation

Case Study (HM KC)

Other BeliefsOther Beliefs

• Only I can feel my pain.• Necessarily, the statement ‘I am, I

exist’ is true every time I utter it.

Three distinctionsThree distinctions

• A priori• A posteriori

• Analytic• Synthetic

Knowledge Truth• Necessary• Contingen

t

Modality

Necessary a priori analytic: my biological brother has the same parents as I do.

Contingent a posterior synthetic: groundhogs climb trees.

Possible?Possible?

Priori Analytic

Nec.

Post. N ? K

Synth. ? N ?

Cont. ? ? N

Pop Quiz!Pop Quiz!

• Water is H2O

• The Prince of Wales is the future King of England

• The morning star (Hesperus) is the evening star (phosphorus)

• The present king of France is bald.• Pegasus is a flying horse

Bacon’s bad habits:Bacon’s bad habits:

• The Idols:– Of the tribe– Of the cave– Of the marketplace– Of the theater.

Of the tribe:Of the tribe:

Of the cave:Of the cave:

Of the marketplace:Of the marketplace:

Of the theater:Of the theater:

• Bacon’s first example: that the heavens move in perfect circles.

PtolemyPtolemyFrom the Almagest, Ch 3 (H11):

What chiefly led them (the ancients) to the concept of a sphere was the revolution of the ever-visible starts, which was observed to be circular, and always taking place about one center, the same [for all].

PtolemyPtolemyFrom the Almagest, Ch 3 (H11):

Suppose that the “star’s motion takes place in a straight line towards infinity, as some people have thought, what device could one conceive of which would cause each of them to appear to begin their motion from the same starting-point each day? How could the stars turn back if their motion is towards infinity? Or, if they did turn back, how could this not be obvious? On such a hypothesis, they must gradually diminish in size until they disappear, whereas, on the contrary, they are seen to be greater at the very moment of their disappearance, at which time they are gradually obstructed and cut off, as it were, by the earth’s surface.”

Ptomely, Cont’dPtomely, Cont’dBut to suppose that they are kindled as they rise out of the earth and are extinguished again as they fall to earth is a completely absurd hypothesis……to sum up, if one assumes any motion whatever, except spherical, for the heavenly bodies, it necessarily follows that their distances, measured from the earth upwards, must vary, wherever and however one supposes the earth itself to be situated. Hence the sizes and distances of the starts must vary… Yet we see that no such variation occurs

The argumentThe argument1. If the heavens do not move spherically, there is one of

two options: either they move linearly to infinity or they are created and destroyed each day.

2. Suppose that the heavens do not move spherically.1. Then either they move linearly to infinity or they are

created and destroyed. (MP 1, 2)2. If they are created and destroyed each day, there

would be variation in their placement.3. There is not. 4. Therefore, they are not created and destroyed each

day. (MT 2, 3)5. Therefore, they must move linearly (DS 4, 1)6. If they move linearly, the stars would appear to get

smaller.7. They do not.8. Therefore, they must not move linearly (MT 7, 6)9. But this is a contradiction.

3. Therefore, the heavens move spherically (Indirect Proof 1-9).

True inductionTrue induction• Bacon’s Method:

1. Draw axioms from experience1. Categorize instances of the

phenomenon in question: existence, closely-related non-existence, degrees

2. Then Induction: reject all that is not present in the negative instances.

2. Derive new experiences from axioms (experimentation).1. Seek contradictory instances.2. Repeat

RationalismRationalism

• Descartes’ Method:

Induction v DeductionInduction v Deduction

• Not Truth Preserving

• Ampliative• Spectral

(reasoning with probability)

• Truth Preserving• Non-ampliative• All or nothing

(reasoning with necessity)

AmpliativeAmpliative

• I saw a white swan

• I saw a white swan

• I saw a white swan

• Therefore, all swans are white

• All swans are white.

• Therefore, the swan that I saw was white.

ProbabilityProbability

• We have 10 male and 10 female freshman in this class.

• Therefore, 50% of all freshmen are male

• 50% of all freshman are male

• Therefore, a freshman chosen at random has a 50% chance of being male.

Simplistic inductivist Simplistic inductivist account of science.account of science.

• Quote on pg. 11 of Hempel1. Observe and record all facts.2. Analyze and classify these facts.3. Derive generalizations about them

inductively.4. Further test those generalizations.

ProblemsProblems

• Problems:1.It would never get started2.Auxiliary hypotheses influence

categorization and observation.3.There are no ‘formal’ or ‘mechanical’

rules for generating inductive hypotheses.

(Brief) History of Color (Brief) History of Color ScienceScience

Basic Schema:

Hermann von HelmholtzHermann von Helmholtz(1821-1894)(1821-1894)

Short = Purple Middle = Green Long = Red

Historical Note:Historical Note:• In 1877, Ladd-Franklin became the first woman

to attend (albeit unofficially) Johns Hopkins where she studied mathematics.

• She wrote a dissertation under the supervision of C.S. Pierce. It was published in 1883, but her Ph.D. was not awarded until 1926!

• Even though she had studied under Helmholtz and had published a great deal in psychological journals, she was never admitted to the American Psychological Association meetings to present her papers.

• While she lectured at John Hopkins, Columbia, Clark, Harvard and Chicago, she never held an official academic post, and she was rarely paid.

• Her book Color and Color Theories was finally published in 1929, one year before her death.

Ladd-Franklin (1847-1930)Ladd-Franklin (1847-1930)IF stimulating the long-wavelength cone yields a red experience, and stimulating the middle-wavelength cone yields a green experience, THEN stimulating both the long and middle-wavelength cone would….

yield an experience of reddish-green

L-F’s argument (L-F’s argument (≈≈1892)1892)

IF stimulating the long-wavelength cone yields a red experience, and stimulating the middle-wavelength cone yields a green experience, THEN stimulating both the long and middle-wavelength cone would yield an experience of reddish-green

Stimulating L and M yields an experience of yellow.

THEREFORE, Helmholtz’s theory is NOT true

Yellow does NOT look like reddish-green.

THEREFORE, yellow is NOT reddish-green.

Good Argument Right?

Why not?Why not?“Helmholtz deemed it illegitimate or at least

untrustworthy to draw conclusions as to physiological processes from the direct psychological character of the sensations”-Von Kries

Helmholtz’s responseHelmholtz’s response

IF stimulating the Long-wavelength cone yeilds a red experience, and stimulating the middle-wavelength cone yields a green experience, THEN stimulating both the Long and Middle-wavelength cone would yield an experience of reddish-green

Stimulating L and M yields an experience of yellow.

THEREFORE, Helmholtz’s theory is NOT true

THEREFORE, Yellow is NOT reddish-green.

Yellow does NOT look like reddish-green.

BUT: One cannot draw conclusions about the physiology of color from this fact, so it does not follow that:

yellow is not reddish-green or greenish-red.

Note:Note:

• The Gestalt Psychologist David Katz made the phenomenology of color appearance the starting point for a theory of color (1908).

ProblemsProblems

• Problems:1.It would never get started2.Auxiliary hypotheses influence

categorization and observation.3.There are no ‘formal’ or ‘mechanical’

rules for generating inductive hypotheses.