Popper inspired scientists. His philosophical views on science have been used within scientific debates to justify one position over another.
* Within biology debates about the classification of organizations, as well as about ecology have seen Popper’s ideas used in this way.
-> Popper believed that science is a search for true descriptions of the world, but insisted that we can never support or confirm scientific theories.
Popper disagreed with the Logical Positivists, especially about developing inductive logic, although he was an empiricist in the broad sense.
* So inductive arguments can never be justified.
* So his philosophy shows what kind of theory of science might be possible if you gave up on induction and confirmation.
His primary aim was to understand science, unlike the Logical Positivists who wanted to develop a general theory of science as part of a general theory of language, meaning, and knowledge
* He wanted to understand the difference between scientific theories and non-scientific theories -> science vs pseudo-science
* Genuine science according to Popper: Einstein’s work
* Pseudo-science according to Popper: Freudian psychology, Marxist views on society and history
-> The problem of distinguishing science from non-science
Falsificationism: Claims that a hypothesis is scientific if and only if it has the potential to be refuted by some possible observation.
* Used to distinguish scientific theories from non-scientific theories
* Goes further by saying that all testing in science has the form of attempting to refute theories by means of observation
-> It is never possible to confirm a theory, not even slightly, no matter how many observations the theory predicts successfully.
The only thing an observational test can do is show that a theory is false
Truth can never be supported by observational evidence
Popper was skeptical of all forms of confirmation and support except deductive logic
Fallibilism: You can never be completely sure that a theory is true, you can never be completely certain about factual issues
* Popper said there’s no way to reasonably increase our confidence in the truth of a theory when it passes observational tests
* Logical Empiricists and most other philosophers of science disagree.
Popper believed we should always maintain a tentative attitude towards our theories no matter how successful they’ve been in the past (e.g. Newtonian physics)
-> Popper’s theory on scientific change also relies on falsification.
Science changes via two-step cycle that repeats endlessly:
1. Conjecture
* A scientist offers a hypothesis that might describe and explain some part of the world
2. Attempted Refutation
* The hypothesis is subjected to critical testing in an attempt to show that it’s false. Once the hypothesis is refuted, we return to #1, a new conjecture is offered.
So a theoretical idea can be refined and modified via many rounds of conjecture and refutation.
Scientists should strive to increase the breadth of application of a theory and increase the precision of its predictions.
Someone who can come up with imaginative, creative, and risky ideas.
Someone with a hard=headed willingness to subject these imaginative ideas to rigorous critical testing.
The 2-step process is similar to Darwin’s explanation of biological evolution in terms of variation and natural selection
* Popper: Scientists toss out conjectures that are subject to critical testing
* Darwin: Populations evolve via a process in which variations appear in organisms in a random or ‘undirected’ way, and these novel characteristics are ‘tested’ through their effects on the organism in its interactions with the environment. Variations that help organisms to survive and reproduce, and which can be passed down via reproduction, tend to be preserved and become more common in the population over time.
One refutation of this is that evolution isn’t a process in which populations ‘search’ for anything.
-> Can we describe a distinctive strategy of investigating the world, a scientific way of handling ideas?
For Popper, theories have the form of generalizations, and they take risks by prohibiting certain kinds of particular events from being observed.
* Ex: All pieces of iron contract when heated.
So how sure can we be that the piece of iron being tested is really iron? How sure can we be of our measurements of the contraction and temperature changes?
Our assumptions about the testing situation and our ability to know that the sample is made of iron still come into question
Thus holism about testing becomes a problem.
We can’t be completely certain about the observation reports that we use to falsify theories
Thus we have to regard the acceptance of an observation report as a a decision. So in Popper’s view, falsification processes are necessarily based on decisions that could be challenged.
This led Popper to shift from describing characteristics of scientific theories to describing characteristics of scientific behavior & modes of thought
So does Popper’s theory fail to differentiate between science and pseudo-science?
Yes: Scientific theories can be handled in a way that makes them immune to falsification, while non-scientific theories can be rejected if people decide to accept claims about particular matters that are incompatible with the theory.
No: A scientific theory is falsifiable via a certain kind of decision, one regarding an observation report
If a hypothesis doesn’t forbid any particular observations, then it’s taking no risks -> so what about theories that don’t forbid an observation, but just say that it’s very unlikely?
Popper contended that probabilistic theories can only be construed as falsifiable in a special ‘in practice’ sense. Once again, decisions, as opposed to the constraints of logic, come into play.
* So now, because of probability thresholds, falsification can occur without being backed up by a deductive logical relation between observation and theory.
We want to build a bridge, and need to use physical theories to tell us which designs are stable and will support the weight that the bridge has to carry.
So we have to choose between types of theories that haven’t been falsified:
A theory that’s been tested many times and passed every test (a.k.a. it’s been corroborated)
A new theory that’s been conjectured but never been tested
Corroboration: It is entirely “backward-looking.” No good reason can be given for believing that past performance isa reliable guide to the future.
* Corroboration is like an academic transcript, which only says something about what you’ve done.
* Confirmation is like a letter of recommendation that says something about what you’ve done, and makes claims of how you’re likely to do in the future.
Hypothetico-Deductive Method:(as opposed to hypothetico-deducitivsm)
Version 1: A combination of Popper’s view of testing and a less skeptical view about confirmation. It’s a process in which scientists come up with conjectures and then deduce observational predictions from them. If predictions occur as expected, then the theory is supported. If the predictions don’t, then the theory should be rejected.
Version 2: Involves a first stage where conjecture is generated from collected observations, which Popper disagreed with because he argued that fact-gathering in scientific procedures can only take place in a way guided by conjecture.
Version 3: Strong inference, which is Popperian testing + the assumption that we can write down all possible theories that might be true in some area, and test them out one by one – we find the true theory by eliminating the alternatives.
The emphasis on exposure and risk, which describes the kind of contact that scientific theories should have with observation, is Popper’s most enduring contribution to science.
* Science tries to formulate and handle ideas in such a way that they’re exposed to falsification and modification via observation.
* This formulation is valuable because it captures the idea the theories can appear to have lots of contact with observation, when in fact they only have a kind of ‘pseudo-contact’ with observation because they’re exposed to no risks.
Risk-taking should be used to distinguish between scientific and unscientific ways of handling ideas, as opposed to theories.
The scientific way of handling an idea is to try to connect it with other ideas, to embed it in a larger conceptual structure, in a way that exposes it to observation
So instead of working out whether theories like Marxism and Freudianism are scientific or not, we should work out whether the main principles of the theories can be handled scientifically or unscientifically (a.k.a. they can have scientific and unscientific versions).
* To scientifically the basic principles of a theory is to try to work out what difference it would make to things we can observe if the Marxist principles were true.