IB Philosophy 6.1.1 the Nature of Science Notes

What Is Science?

1. Philosophy of science examines the foundations, methods, and implications of scientific inquiry, asking what makes science a distinctive and reliable way of understanding the world. This unit explores whether science aims at truth, how it develops over time, and whether its methods can be justified philosophically.
2. The central question of this topic is deceptively simple: what is science? While most people associate science with laboratories and equations, philosophers probe deeper, asking whether science is defined by its method, its subject matter, or its aims.
3. Karl Popper argued in The Logic of Scientific Discovery (1934) that what makes a theory scientific is its ability to be falsified (proven wrong by evidence). His theory, called falsificationism, replaced older views that science works mainly by collecting confirming examples, and it remains one of the most influential answers to the question of what separates science from non-science.
4. Thomas Kuhn argued in The Structure of Scientific Revolutions (1962) that science does not progress by steadily adding facts. Instead it moves through paradigm shifts: long periods of routine work within a shared framework (which Kuhn calls normal science) are suddenly overturned by revolutionary upheavals. The shift from thinking the Sun orbits the Earth to knowing the Earth orbits the Sun is the classic example.
5. Paul Feyerabend argued in Against Method (1975) that no single set of methodological rules can account for the history of science. Breakthroughs like Galileo's defence of heliocentrism often required violating the accepted rules.
6. His view, which he called epistemological anarchism (the idea that no single fixed method defines science), challenges the assumption that science must follow one correct set of rules, whether those rules come from older verification-based thinking or from Popper's falsification-based approach.
7. Science relies on observation, experiment, and measurement as its primary tools, but even these are philosophically complicated. A key puzzle is whether observation can ever be truly theory-neutral (free from the observer's existing beliefs and assumptions), or whether what we see is always filtered through the theories we already hold. This has been one of the most debated questions in twentieth-century philosophy of science.
8. This topic connects to the overarching questions of Unit 6: whether science aims at truth, what the central feature of science is, and what differentiates science from pseudo-science. These questions recur throughout the philosophy of science and inform debates in demarcation (6.1.2) and scientific methodology (6.1.3).

Does Science Aim at Truth?

1. The question of whether science aims at truth is one of the most fundamental debates in the philosophy of science.
2. Scientific realists argue that the goal of science is to discover how the world really is, and that our best scientific theories are approximately true descriptions of reality.
   1. The most powerful argument for scientific realism is the no-miracles argument: the success of science in making accurate predictions and enabling technological innovation would be miraculous if scientific theories did not at least approximately describe the world as it actually is.
3. Anti-realists challenge scientific realism in several ways.
4. Instrumentalists argue that scientific theories are merely useful tools for predicting observations, not accurate descriptions of reality.
   1. For the instrumentalist, the question of whether scientific theories are truly accurate descriptions of reality is irrelevant or, at best, unanswerable.
   2. Instrumentalists point to the history of science as a reason to distrust claims of truth: earlier theories that seemed successful, such as the Ptolemaic model of epicycles (extra loops added to explain planetary motion) were eventually abandoned.
   3. If supposedly successful theories can be overturned, calling them 'true' seems like it adds nothing useful.
5. What matters is whether a theory generates accurate predictions and useful interventions.
   1. Ptolemaic astronomy, for instance, produced remarkably accurate predictions of planetary positions for over a millennium, and an instrumentalist counts this as fully successful science regardless of whether epicycles really existed.
6. For instrumentalism, the only question worth asking is whether a theory generates accurate predictions and useful results.
7. Calling theories 'true' or 'false' adds a metaphysical burden (a philosophical claim about hidden reality) that science simply does not need.

Constructive Empiricism and the Observable/Unobservable Divide

1. Van Fraassen draws a sharp line between observable and unobservable entities, noting that while we can observe cell division under a microscope, we cannot directly observe entities like electrons or quarks but must infer their existence from experimental results.
2. Constructive empiricism, developed by Bas van Fraassen, holds that the aim of science is not truth but empirical adequacy: a theory is successful if it accurately predicts what we can observe, regardless of what it says about unobservable entities like quarks or dark matter.
3. Van Fraassen argues that science only requires us to accept a theory as empirically adequate, meaning it correctly predicts everything we can actually observe, without us needing to believe its claims about invisible entities.
   1. Atomic theory is a good illustration: for decades, chemists used atomic models to predict chemical reactions with great accuracy, while many scientists, including the physicist Ernst Mach, denied that atoms literally existed as physical things.
   2. The theory was empirically adequate long before atoms could be observed in any meaningful sense.