philosophy of science 1-3.1

empiricism

• knowledge justified by experience

• experimental + observational evidence

• locke, hume

• traditionally: tabula rasa (clean slate)

rationalism

• some knowledge can be justified by pure reason

• often fundamental/general claims: causation, space, time

• descartes, kant

• traditionally: some knowledge is innate

modern debate between empiricism/rationalism

less about where knowledge comes from → more about how knowledge is justified

empiricism = experience, evidence

rationalism = reason, logic

descriptive vs normative claims

descriptive

• what is

• describes

• observes

normative

• what ought to be

• prescribes

• rules/standards

Locke + representational realism

Locke:

• we don’t directly perceive external objects themselves

• they cause representations/ideas in our minds through our senses

• qualities → ideas

→ creates problem of external world skepticism (how do we know our mental representations accurately depict reality?

Hume’s two kinds of reasoning

1. relations of ideas

• certain through thought

• deductive

• a priori

• contradiction is impossible

• ex: geometry, algebra, arithmetics

2. matters of fact

• based on experience

• could always be otherwise

• a posteriori

• inductive

• ex: the sun rose today, therefore it will rise again tomorrow

induction vs deduction

deduction (extracts information)

premise + premise = conclusion (already contained in premise)

• does not add new information

• certain if reasons (premises) are valid

• ex: all lawyers are politicians + some lawyers are corrupt = some politicians are corrupt

induction (expands information)

evidence/experience → conclusion that goes beyond evidence

• ampliative = adds information

• not certain

• used to make predictions/generalizations

• ex: every swan ive seen is white → all swans are probably white

the problem of induction

How can past experiences logically justify claims about unobserved/future cases?

Hume’s point

• matters of fact are based on experience

• experience shows constant conjunctions/patterns

• but there is no logical contradiction in the opposite also occurring

• therefore, induction can never give the same certainty as deduction

past ≠ future

verificationism & logical positivism

logical positivism: a claim is meaningful only if it can be tested and verified through physical observation or proven true by logic\

verificationism: a statement is cognitively meaningful if it can be verified through experience or is true by definition (analytic truth)

vienna circle

• logical positivism

• logical empiricism

• verificationism

to understand the meaning of a statement you must know how it could be verified

meaningful statements are:

• empirically verifiable

  OR

• logically true

problem: problem of induction

• empirical verification depends on observations, but past ≠ future

verification principle’s self-refutation

self refutation: can the verification principle itself be verified?

if analytic (true simply because of the meaning/definition of the words):

• merely a definition, not an empirically established fact about language/reality

if synthetic (a substantive claim about how language/reality work):

• not empirically verifiable

→ so by its own standards, the principle would be meaningless

Duhem-Quine Holism

scientific hypotheses are NOT tested in isolation

• if a prediction in an experiment is wrong ≠ hypothesis is false

→ could be affected by other influences

Duhem-Quine → scientific testing is holistic, not isolated

phenomenalism vs physicalism

phenomenalism

• Reality is fundamentally made up of conscious perceptions and sensory experiences rather than independent physical objects

• experiences are internal/private

• physical objects and the external world do not exist independently of human perception

physicalism

• Everything that exists is ultimately physical (matter, energy, fields, spacetime, and physical laws)

• describes observable physical objects/events

  • spatiotemporal coordinates

Kant’s synthetic a priori

a priori:

• independent of particular sensory experience

• necessary + universal

a posteriori:

• based on sensory experience

• contingent

analytic:

• truth by meaning/concept

• doesnt add substantive information

synthetic:

• adds information beyond whats contained in the concept

synthetic apriori: adds knowledge (synthetic) but is universally true/necessary (a priori)

→ causation, mathematics, pure science

Hume vs Kant

Hume

• empiricist

• knowledge of matters of fact come from experience

• causation learned from constant conjunction

• mathematical truths = a priori

• skeptical about induction

Kant

• rationalist

• some knowledge has an a priori basis

• causation has an a priori component

• mathematics → synthetic a priori

  • tries to explain how necessary knowledge is possible

phenomenalism + external world skepticism

phenomenalism

• world can be understood as a patterned collection of sensations

• doesnt require direct access to mind-independent objects

representational realism

• we experience representations, not objects directly

• raises external-world skepticism

people → ideas

descartes:

• rationalism

• systematic doubt

• senses can deceive

• some knowledge innate/pure reason

Locke:

• empiricism

• tabula rasa

• representational realism

• ideas/qualities

Hume:

• empiricism

• matters of fact vs relations of ideas

• problem of induction

• causation = experienced constant conjunctions

Kant:

• rationalism

• synthetic a priori

• mind contributes structures to experience

vienna circle:

• logical positivism/verification

Duhem + Quine:

• holistic testing