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.
4. Van Fraassen's position offers a middle path between full-blooded realism and dismissive instrumentalism: take the observable predictions seriously but remain agnostic about what lies beneath.
5. The debate between realism and anti-realism is sharpened by the problem of underdetermination: for any body of evidence, multiple incompatible theories can be constructed that are equally consistent with the data. This suggests that evidence alone cannot determine which theory is true.
6. The underdetermination thesis, associated with W.V.O. Quine, holds that for any body of evidence, there will always be multiple incompatible theories that fit the data equally well.
   1. Consider a classic illustration: in the early sixteenth century, both the Ptolemaic geocentric model and the Copernican heliocentric model yielded broadly comparable predictions of planetary positions.
7. The observational evidence available at the time could not determine which model was correct. If evidence alone cannot choose between rival theories, then something beyond evidence, such as simplicity, elegance, or explanatory scope, must guide theory choice.
8. Underdetermination thus challenges scientific realism directly: if evidence can never pick out one uniquely true theory, the realist claim that our best theories are approximately true becomes harder to sustain.

Pessimistic Induction, Popper, and Kuhn

1. The pessimistic induction is a further challenge to scientific realism.
   1. The argument goes like this: look back through history and you find that many theories once considered highly successful, such as the caloric theory of heat (which treated heat as a weightless fluid) and the phlogiston theory (a substance supposedly released during burning), were eventually abandoned as completely wrong.
   2. If past successful theories turned out to be false, the realist faces a pressing question: why should we believe that our current theories are any more trustworthy?
2. Popper's view occupies a distinctive position in this debate: he argued that science does not aim to prove theories true but to subject them to rigorous testing.
3. A theory that survives repeated attempts at falsification is what Popper called well-corroborated: it has been tested hard and not broken yet. Corroboration (surviving severe tests) is not the same as proof, but it gives us rational grounds to prefer that theory over untested rivals.
4. Kuhn's account of paradigm shifts (revolutionary replacements of entire scientific frameworks) raises a further question for realism. If science periodically scraps its whole framework and starts again, it is unclear whether each new paradigm is getting closer to the truth, or simply offering a different way of organising experience.
5. For IB Philosophy, the realism versus anti-realism debate is a central analytical framework. Students should be prepared to evaluate the strengths and weaknesses of each position and to apply them to specific examples from the history of science.

Observation, Experiment, and How Science Develops

1. Observation has traditionally been regarded as the foundation of scientific knowledge. The empiricist tradition, stretching back to Francis Bacon and John Stuart Mill, holds that all scientific knowledge ultimately derives from sensory experience and careful observation of the natural world.
   1. However, the idea that observation is a neutral, theory-free activity has been challenged by philosophers of science.
   2. N.R. Hanson introduced the concept of theory-ladenness of observation: what scientists observe is shaped by the theoretical framework they already hold, meaning that observation is never purely objective.
2. Hanson illustrated this with a vivid example: a physicist and an untrained observer looking at the same cloud-chamber track see radically different things.
   1. The physicist sees the trajectory of an electron, while the untrained observer sees only a white line.
   2. Both the physicist and the untrained observer receive the same sensory input, yet what they see differs because the physicist's theoretical training shapes perception itself.
   3. Hanson concluded that observation is always an interpretation filtered through the observer's concepts and prior knowledge, never a neutral recording of bare facts.
3. Kuhn reinforced this point by arguing that scientists working within different paradigms (shared scientific frameworks) literally see the world differently.
   1. A paradigm provides the theories, methods, and standards that define normal science, the day-to-day problem-solving activity of working scientists.
4. Experimentation is often seen as the hallmark of the scientific method.
   1. Controlled experiments allow scientists to isolate variables, test hypotheses, and establish causal relationships.
5. The philosophical significance of experimentation lies in its role as a check on theoretical speculation, ensuring that scientific claims remain grounded in observable evidence.

Measurement, Methodology, and Scientific Development

1. Measurement and quantification have become central to modern science, transforming qualitative observations into precise, reproducible data.
   1. The development of sophisticated instruments (telescopes, microscopes, particle accelerators) has extended the reach of scientific observation far beyond unaided human perception.
2. Popper's falsificationist methodology reframes the aim of science: science does not aim to prove theories true but to subject them to the severest tests possible, accepting only those that survive.
   1. Thomas Kuhn's account of paradigm shifts is examined in depth in 6.1.2. The cycle goes: normal science, then the build-up of anomalies (results the current framework cannot explain), then crisis, then revolution.
   2. The Copernican revolution serves as the primary case study for this.
   3. For the nature of science, Kuhn's key point is that observation itself is shaped by the paradigm scientists work within.
3. Feyerabend's rejection of universal method and his epistemological anarchism are examined in 6.1.2. He challenges scientism, the assumption that science is the sole legitimate source of knowledge.
4. The tension between positivist approaches (emphasizing verification, observation, and logical rigor) and post-positivist critiques (emphasizing the social, historical, and theoretical dimensions of science) is important to note for exam purposes. Feyerabend's work, alongside Kuhn's, represents the post-positivist turn.
5. Understanding how science develops is essential for evaluating scientific claims in everyday life. Questions about whether a particular finding is reliable, whether a scientific consensus should be trusted, and how scientific revolutions occur all depend on the philosophical frameworks introduced by Popper, Kuhn, and Feyerabend.

The Limits of Science

1. The question of whether there are some things science will never be able to answer lies at the heart of debates about the scope and limits of scientific inquiry. While science has proven extraordinarily successful at explaining natural phenomena, philosophers have identified several domains where scientific methods appear to reach their boundaries.
2. Moral questions present one of the clearest limits to science. Science can describe how the world is, but it cannot determine how the world ought to be.
3. The distinction between descriptive facts and normative values, sometimes called the is-ought gap following David Hume, suggests that ethical judgments require philosophical rather than scientific reasoning.
4. Hume's point rests on basic logic: facts about how the world is cannot, by themselves, tell you what ought to happen. No matter how many descriptive facts you have, you cannot reach a moral conclusion without adding a value judgement. Science gives you the facts; only moral reasoning can supply the oughts.
5. Consider climate science: empirical research can establish that burning fossil fuels raises atmospheric CO₂ concentrations and that rising concentrations drive global warming.
   1. But the question of what we should do about it requires a further, distinctly moral premise, for example that we have an obligation to future generations, or that environmental destruction is intrinsically wrong.
6. Science provides the facts, while philosophy and ethics must supply the values. This is-ought gap means that science, no matter how advanced, cannot replace moral reasoning.

Consciousness, Metaphysics, and the Challenge of Scientism

1. Questions of consciousness pose a profound challenge to scientific explanation. The hard problem of consciousness, identified by David Chalmers, asks why physical processes in the brain give rise to subjective experience at all.
2. Neuroscience can identify which parts of the brain are active during consciousness, known as the neural correlates of consciousness (the brain activity that goes along with each experience).
   1. But what it actually feels like from the inside, the colour red as you see it or pain as you feel it, may elude purely scientific explanation.
3. Aesthetic and existential questions also fall outside the scope of science.
   1. Questions about the meaning of life, the nature of beauty, or the significance of human existence require forms of reflection that go beyond empirical investigation and measurable outcomes.
4. Metaphysical questions, such as why there is something rather than nothing, or what the ultimate nature of reality is, may be beyond the reach of science because they concern the framework within which science itself operates.
   1. Science presupposes the existence of a law-governed natural world but cannot provide an ultimate explanation for why such a world exists.
5. The concept of scientism describes the overextension of scientific methods into domains where they do not apply.
6. Feyerabend warned against treating science as the sole legitimate source of knowledge, arguing that this impoverishes human understanding by excluding artistic, spiritual, and philosophical forms of inquiry.
   1. He pointed to how indigenous knowledge systems, including traditional medicine, agricultural practices developed over millennia, and navigational techniques used by Pacific Island peoples, were routinely dismissed as mere superstition by Western science.
   2. Yet modern researchers have repeatedly confirmed the efficacy of traditional remedies, such as artemisinin from Chinese medicine, now a frontline malaria treatment.
7. If scientism leads us to disregard such knowledge systems, Feyerabend argued, it impoverishes rather than enriches human understanding. Science is one powerful way of knowing, but treating it as the only legitimate way blinds us to genuine knowledge produced through other traditions.
8. Kuhn's work also implies limits to scientific knowledge. If scientific understanding is always shaped by the prevailing paradigm, then there may be aspects of reality that are invisible or inexpressible within any given scientific framework.