phil 3318: philosophy of science

Phil 3318: Philosophy of Phil 3318: Philosophy of ScienceScience

Categorization & the influence of Auxiliary hypotheses

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.

The DN Model of The DN Model of ExplanationExplanation

• Explanations are sound arguments (valid w/ true premises) that entail the event to be explained.

L1, L2, … Ln

F1, F2, … Fn

E

Explanans

Explanandum

Laws (usually conditionals)Facts

Phenomenon Explained

ExampleExample

• Explanations are sound arguments (valid w/ true premises) that entail the event to be explained.

For all cases, if you stimulate the L cone, the subject experiences a sensation of red.

My L cone is stimulated

Therefore, I have a sensation of red.

Explanans

Explanandum

H-DH-D

• Notice the relation to the H-D method:

For all cases, if you stimulate the L cone, the subject will experience a sensation of red. I am not experience red

Therefore, my cone is not stimulated

Explanans

Explanandum

Notice also that all explanandi are potential predictions!

When predictions fail:When predictions fail:

• Auxiliary hypotheses are at fault!

For all cases, if you stimulate the L cone and the M cone, the subject will experience a sensation of reddish-green.

My L and M cones are stimulatedTherefore, I am experiencing reddish-green

Explanans

Explanandum

When predictions fail:When predictions fail:

For all cases, if you stimulate the L cone and the M cone and the psychological character of sensations tells us (with certainty) what color is to be explained, then the subject will experience a sensation of reddish-greenMy L and M cones are stimulatedTherefore, I am experiencing reddish-green

Explanans

Explanandum

(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).

Definitions of ‘Memory’Definitions of ‘Memory’

• Maybe, my memory for IP addresses isn’t really ‘memory’?

• http://inquiry.wustl.edu/newFrames/modules.php?mod_id=437

For all normal humans, we only have the ability to remember 7 digits +/- 2

I’m a normal human

Therefore, I can only remember 7 digits +/- 2

Delineating Phenomena Delineating Phenomena w/in ‘Memory’w/in ‘Memory’

Raise your hand if you Raise your hand if you had:had:

• BAG• DOG• FAN• GAS• HAT• KID• LOG• PAD

• SOD• VEX• WIN• ZIP

Learning CurveLearning Curve

Philosophers:Philosophers:

• (Plato / Aristotle?), Bergson, Russell, Ryle all distinguish between knowing how and knowing that. This distinction is transposed into memory:– I remember how to do arithmetic.– I remember that 2+2=4.– I remember how to get to Sears– I remember that Sears is on the corner of

…

Further Distinctions:Further Distinctions:

• I just remembered that I am supposed to be in class!

• Remember when Janet Jackson had her ‘wardrobe malfunction’?

• Remember where you were when the Towers collapsed?

• Pavlov’s dog.• Priming

Motor Skills

Memory

LTMSTM

Non-Declarative (Implicit)

Declarative (Explicit)

Episodic (Events)

Semantic (Facts)

Priming Classical Conditioning

1. Splitting Dissociable Kinds 1. Splitting Dissociable Kinds of Memoryof Memory

H.M. from the Perspective H.M. from the Perspective of Cognitive of Cognitive

NeuropsychologyNeuropsychology• Develop

Taxonomies of Memory

• Characterize Different Types of Memory

• Understand Neuro-cognitive Mechanisms

Memory

LTMSTM

Non-Declarative (Implicit)

Declarative (Explicit)

Episodic (Events)

Semantic (Facts)

Priming Classical Conditioning

Motor Skills

The Hippocampus The Hippocampus

Identify set of tasks on

which H.M. succeeds (TS).

Identify set of tasks on

which he fails (TF).

Conjecture some cognitive

faculty required for each

task in TS and for no task

in TF.

On which tasks does H.M. On which tasks does H.M. succeed?succeed?

• Perceptual and motor.

• I.Q. tests.• Mirror Drawing.• Gollins Partial

Pictures.• Priming.• Classical and

Operant Conditioning.

• Language.

On which tasks does H.M. On which tasks does H.M. fail?fail?

• Conscious recognition of facts and events (Squire)

• Regardless of kind of test (free recall, cued recall, recognition)

• Regardless of material (e.g., words, digits, faces, mazes, life events)

• Regardless of sensory modality• Conclusion: Loss of “Declarative

Memory”

Dissociation and the Dissociation and the Taxonomy of MemoryTaxonomy of Memory

• A major theme in current studies of both humans and experimental animals is that memory is not a single entity but is composed of separate systems (Weiskrantz, 1990; Squire, 1992; Schacter and Tulving, 1994). The dissociation between declarative (explicit) and nondeclarative (implicit) memory is based on studies of experimental animals as well as amnesic patients and normal subjects showing that fact-and-event memory is distinct from other kinds of memory (skills, habits, and priming).– Squire and Knowlton

Memory Dissociation Memory Dissociation Argument in PhilosophyArgument in Philosophy

• Some X is a ‘natural kind’ iff in no possible world do parts of X exist without the whole and X still exists in that world (I.e. H2 w/out the O is not water).

• Hume’s claim: Two events are causally connected if and only if one might occur without the other.

• Why?– Because nothing can cause itself.– And if two events are necessarily conjoined, they

are the same event (with the exception of two events that are both caused by a third event like ‘Socrates dying’ and ‘Xantippe becoming a widow’).

Memory Dissociation Memory Dissociation Argument in NeuroscienceArgument in Neuroscience

1. Declarative memory and procedural memory can be independently disrupted.

2. Mechanistic Splitting: If two kinds can be independently disrupted, then they are explained by two distinct mechanisms.

3. Procedural and Declarative Memory have distinct mechanisms.

4. No Dissociable Mechanisms. Natural kinds are explained by one kind of mechanism. If there are two distinct mechanisms for a putative instance of a kind, there are really two kinds, one for each mechanism.

5. So Procedural and Declarative Memory are distinct natural kinds.

Videos!Videos!

• KC