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//************* Hansen on Observation - September 26th, 2019 ****************//
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- Okay, we read a paper by N. R. Hansen - let's talk about it!
    - Norman Russell Hansen had a pretty exciting life: he served as a fighter pilot in WWII, did graduate work at Oxford, and went on to found the 1st Philosophy of Science program in the U.S. at Indiana University

- So, what was the main point of this paper, and why might it be a critique of logical empiricism?
    - First off, let's cover a little background
        - Many scientists (and ESPECIALLY logical empiricists) view observations as ways of "testing" existing theories, and most scientists in Hansen's day viewed observation as a pretty straightforward thing: we just "look" at it and see the same thing!
            - Most examples the empiricists give, like seeing how high a mercury tube goes on a barometer, make observations seem obvious - they rarely give complicated observation examples
        - Here, Hansen is pushing back on that and saying that observation is NOT straightforward - it's complicated! In fact, he says some pretty controversial stuff!
            - Hansen asks how 2 people can look at something like an amoeba and "see" 2 different things
                - From a "Physicalist" view, people do literally see the same thing: the same photons hit their retinas and present the same colors, shapes, and so forth
            - For Hansen, though, we never "see" raw sensory data: we always filter it through our mental lens. As he puts it, seeing is a type of EXPERIENCE
                - Hansen is trying to argue that observation itself is "theory-laden;" that people who believe different things might literally see different things from the same physical stimuli, and have different experiences (e.g. the duck-rabbit)
                    - Now, other people pushed back on Hansen and tried to argue that this cognitive processing is fairly low-level and isn't significantly affected by our beliefs (i.e. that the differences were interpretative, with the immediate processing being near-identical between people)
        - Hansen believed that this theory-ladenness was a pervasive feature of all scientific practice
    - So, if we grant that Hansen is right and that observations ARE theory laden, what are its implications for testing theories?
        - Many people would worry that when we test theories, we would end up unconsciously having "biased tests" towards certain theories, and that what we see would then be influenced by our theories in the first place
        - The Vulcan case is a possible example here; perhaps they saw a comet or some other item, and interpreted it totally within a Newtonian framework
            - In Professor Biddle's own research, he was doing some studies on cancer research, and oftentimes they'll get a sample from a patient that someone will "score" to determine how cancerous it is - and one of the techniques they use is "Gleason Scoring," where the more disordered a patch of cells is, the more likely it is to be cancerous
                - These photos of cells are often REALLY complicated - it's not just "how high is the mercury?"
                - As it turns out, different pathologists would regularly give different scores based on this scale (e.g. a breast cancer pathologist would be more likely to find evidence of breast cancer in a tissue sample) - and the disagreement was serious! In 40% of cases, they gave completely different "danger levels" for the patient
                    - Part of the reason for this is because many aspects of the scale are subjective - is the skin closer to this pattern or that pattern? Is this a type 4 or a type 3?

- So, what does this have to do with logical empiricism?
    - The main issue is that there isn't a clear, "obvious" stream of data to form a hypothesis or to test a hypothesis - people's interpretation of the data is subjective, and that deals a heavy blow towards doing any sort of "mathematical" probability assessment for a hypothesis being true

- Alright; we'll be reading Thomas Kuhn's "The Structure of Scientific Revolutions" next week, which is probably the most influential book in this field in the last 50 years