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Hanson There’s more to seeing than meets the eyeball…
Observation: ordinary and scientific • Its role in accounts of scientific reasoning • Hanson’s arguments that observations are “theory-laden” • Scientific observations: How and what the Hubble system “observes”: … • Preview of Kuhn using Hanson’s arguments
Part I Why does getting straight about the nature of observations matter to our understandings of science?
Observation In philosophy, it was long accepted that: • Facts are directly given (via observation) to unprejudiced observers with normal sensory receptors… Observations are independent of theory… • So, any two or more observers looking at the “same thing” will observe “the same thing” • Hence, observations constitute a firm and reliable foundation for science…
“The obviousness” of “observation” including scientific • For those advocating “The Inductive Method,” observation came first and generalizations and hypotheses only later. • For those advocating “Sophisticated” Inductivism and Falsificationism, observations were the foundation by which theories are confirmed or falsified. • In our reading, Duhem does not discuss observation in detail when arguing for Holism (but he does in a quote in Hanson’s article). • Do observations (including experimental results) constitute a firm “foundation” for the logic of justification – i.e., for the testing of hypotheses?
Observation • Are facts “directly given” via observation to unprejudiced observers with normal sensory receptors… • We have considered cases in which objects and events that are unable to observed directly are proposed to explain what we can observe. • Are observations independent of theory? • Hmmm… debris in bubble chambers • Imperfections or jury-rigging as evidence of evolution • Cave paintings… • Evidence of neutrinos… • So, can observation constitute a firm and reliable foundation for science?
Part II • Hanson’s arguments as to why observations are “theory-laden” and, thus, as fallible as the theories they presuppose • Are many layered, building from simple cases to more complex ones • Are frequently interrupted by objections • The interlocutor has a formula that keeps being repeated, and Hanson keeps responding to…
Observation The general argument • There are two senses of ‘seeing’ • The physical processes involved that result in 2 tiny inverted images on each retina (which we do not see) • The visualexperience of seeing – what we do see. • Observation, which is seeing in the second sense (visual experience), is not solely determined by the physical processes involved in the first sense. Prior experience, expectations, conceptual schemes and language help shape what we “see”.
Observation • The physical process of “seeing” • Light traveling from an object etches 4 inverted images on our retinas and that information is sent, via the optic nerves, to our brains. If two of us are looking at the same object, from the same perspective, and similar lighting, etc… the images on our retinas are the same as is the information sent via the optic nerves. • Yet we may not seeing the same thing in the sense of our visual experiences.
Observation • There is the visual experience of seeing. • What we, in fact, see in this sense is notsolely determined by the object, light rays coming from it, or the retinal images they etch. • Concepts, prior experience, expectations and general theories help shape what we see in this sense (or observe).
Observation • Hanson’s important caveat: • He never denies that there is a world of objects and events independent of us or that it places constraints on what we can or do see • Indeed, that observation is theory-laden would not be a surprising result if we did not believe in a reality independent of us, our minds, preconceptions, wishes, etc.
Observation • Layers of evidence and argument • Optical illusions or gestalt “experiences” • The object you are looking at does not change, the physical processes (including the images on your retinas) do not change.. yet you can “flip” between what you “see” in the sense of visual experience • The eye is not a camera • Gestalt experiments • Anomalous cards: demonstrate that expectations help to shape what you see, and that you can learn to see.
Observation • Layers of evidence and argument • Knowledge and what we see
Knowledge and what we see “Enter a laboratory; approach the table crowded with an assortment of apparatus…. An experimenter is inserting into small openings in the metal ends of ebony-headed pins; the iron oscillates, and the mirror attached to it throws a luminous band upon a celluloid scale. The backward and forward motion of this spot enables the physicist to observe the minute oscillations of the iron bar. “But ask him what he is doing. Will he answer “I’m studying the oscillations of an iron bar which carries a mirror”? No, he will say he is measuring the electric resistance of the spools. If you are astonished, if you ask him what his words mean given what you and he have actually observed, he will answer that your question requires a long explanation and you should take a course in electricity.”
Observation • Conceptual schemes and what we see • Cross cultural differences • Color schemes • Red, white and black • Mathematical systems • 1, 2, 3, many • Two dimensional representations of three dimensional objects
Conceptual schemes and language What do you see? What does a baby see? What does a three year old see? What does an adult who has never been introduced to apples see? Why is this “an apple” rather than a puddle of apple stuff an apple-ing event undetached apple parts an instantiation of the Platonic form Applehood
Observation • An important issue raised by the “interlocutor” • The formula: In each of Hanson’s examples, two people do see the same thing; they just interpret it differently. • The point of the formula: keep “seeing” – that is, observation – as firm and reliable as it’s been thought to be. • Hanson: There aren’t two steps we experience, first seeing and then interpreting. We just see!
Observation • An important issue raised by the “interlocutor” • The formula: In each of Hanson’s examples, two people do see the same thing; they just interpret it differently. • ‘Interpretation’ has a perfectly precise meaning. It sometimes involves figuring out what we are looking it isn’t clear… or looking for the meaning of a text. It does not belong here, in the case of ordinary seeing which just happens.
Observation • The formula: In each of Hanson’s examples, two people do see the same thing; they just interpret it differently. • It happens instantaneously, so we’re unaware we are doing it… • Hanson: instantaneous interpretation, like some other ideas in the history of philosophy, is just plain spooky.
Scientific observations Important days in the history of the universe • Dec. 30, 1924: The day the universe got bigger • Using a new telescope, Edwin Hubble made 2 major discoveries • There are galaxies other than our own! We now know there are more than 100 billion galaxies… • Galaxies are, on average, moving away from us
Scientific observations • May 13, 1965: the day we “heard” The Big Bang • Two young radio astronomers stumbled across its “afterglow” • Discovered a source of irremovable static in a sensitive microwave antenna • It was the microwave background of radiation that exists as a remnant of The Big Bang
Scientific observations and the Hubble We should speak of “The Hubble System,” of which the telescope and its parts (cameras and other features) are only a part We should also note that the Hubble does not work by magnifying images, but by being able to take in great amounts of light And we should note that the Hubble does not include cameras in the normal sense… but light collectors .. And so does not itself produce the images NASA presents.
Scientific observations and the Hubble The collected data is then “calibrated” by scientists and engineers… Calibrated? Where do the colors come from in the Hubble images we see? Why do the images have a funny shape?
Kuhn How what scientists observe changes after a revolution
Kuhn: Observation and scientific revolutions • Paradigms and observations (or paradigms and what exists…) • “Examining the record of past research… the historian of science may be tempted to exclaim that when paradigms change, the world itself changes with them” • Scientists adopt new instruments and look in new places. • Scientists see new and different things when looking with familiar instruments in places they have looked before.