Hello Philosophers! Welcome to the Philosophy of Science!

This optional theme is a fascinating journey where we stop just doing science and start thinking critically about what science actually is, how it works, and whether it truly tells us the ultimate truth about the world.

Don't worry if you find scientific concepts challenging; we aren't studying physics or chemistry here! We are studying the methods, assumptions, and limitations of the scientific endeavor itself. This module is essential for understanding the unique authority that science holds in the modern world.

What is the Philosophy of Science?

It is the branch of philosophy that investigates the foundations, methods, implications, and status of science.

Section 1: The Demarcation Problem – What Separates Science from Everything Else?

The first major philosophical hurdle is defining the boundary between genuine science and non-science (or pseudoscience). This is known as the Demarcation Problem.

Why is Demarcation Important?

We rely on science for crucial decisions (medicine, climate policy, technology). We need a principled way to distinguish a scientifically valid claim (e.g., vaccines work) from a pseudoscientific claim (e.g., crystal healing cures cancer).

The Early Answer: Logical Positivism and Verificationism

In the early 20th century, a group of thinkers called the Logical Positivists proposed that a statement is meaningful and scientific only if it can be empirically verified (tested through observation).

  • Key Concept: Verificationism
  • Definition: A statement is scientific if it is possible, at least in theory, to verify (prove true) its claims through empirical observation or testing.
  • Analogy: If I say, "There is a blue pen on my desk," you can verify this by looking. If I say, "The universe is powered by invisible happy spirits," there is no possible observation that could verify this claim, so the Positivists would argue it is not scientific.

Quick Review: Verificationism struggled because how many observations are enough to *verify* a universal law (like "All metals expand when heated")? One million observations might not verify the one-million-and-first.

Section 2: The Core Methodological Challenge – The Problem of Induction

To understand how science tries to discover general laws, we must look at Inductive Reasoning.

A. Inductive Reasoning (Generalizing)

Science often works by observing many specific instances and then formulating a general law. This move from the specific to the general is Induction.

  • Example:
    1. Swan A is white.
    2. Swan B is white.
    3. ... Swan Z is white.
    4. Inductive Conclusion: Therefore, all swans are white.
B. David Hume and the Problem of Induction

The Scottish philosopher David Hume (18th Century) highlighted a massive philosophical problem with induction:

  • The Problem: Induction is based purely on the habit or assumption that the future will resemble the past. We have no logical justification for this assumption.
  • Think of it this way: We assume the sun will rise tomorrow only because it has risen every day before. But the fact that something *has* happened repeatedly does not logically guarantee that it *will* happen again. This assumption is simply a matter of belief, not logical necessity.
  • Hume argued that scientific laws, derived inductively, are therefore built on shaky philosophical ground.

Key Takeaway: If science relies on induction, and induction is philosophically unjustifiable, then the entire structure of scientific knowledge seems uncertain.

Section 3: Karl Popper and Falsificationism – An Alternative Approach

Karl Popper (20th Century) was deeply troubled by the Problem of Induction. He rejected the idea that scientists should try to verify (prove true) their theories. Instead, he argued science should try to falsify (prove false) them.

A. Falsificationism as the Solution to Demarcation

Popper proposed that what makes a theory truly scientific is not that it can be proven true, but that it must be capable of being proven false.

  • Key Concept: Falsifiability
  • Definition: A theory is scientific only if it makes specific, testable predictions that, if they fail, would show the theory to be wrong.

Popper used this concept to solve the Demarcation Problem:

  • Science (e.g., General Relativity): Makes risky predictions. If Mercury’s orbit did not match Einstein's calculations, the theory would be *falsified*.
  • Pseudoscience (e.g., Astrology or Freudian Psychoanalysis): These theories are often constructed so that they can explain any outcome. They are never truly at risk of being proven wrong.
B. Popper’s Method: Trial and Error

Popper saw scientific progress as a process of ruthless elimination.

  1. Hypothesis: Formulate a bold, risky claim (a conjecture).
  2. Test: Design the toughest experiment possible to try and refute the hypothesis.
  3. Outcome 1 (Falsified): If the evidence contradicts the hypothesis, we discard the theory and learn from the mistake.
  4. Outcome 2 (Corroborated): If the evidence fails to contradict the hypothesis, the theory is said to be corroborated.

Important Point to Remember: Corroborated does *not* mean proven true! It only means the theory has survived the best attempts to falsify it *so far*. A theory remains scientific only as long as it is potentially falsifiable in the future.

Common Pitfall to Avoid

When writing about Popper, do not say the goal of science is to find "true laws." For Popper, the goal is to eliminate false theories, bringing us closer to the truth, even if we never reach absolute certainty.

★ Quick Popper Mnemonics ★

Popper wants to Push theories over.
Falsifiability is the Foundation of Fine science.

Key Takeaway: Popper shifts the focus from verification to refutation, transforming the problem of induction into a matter of deductive logic (if 'P implies Q' and 'not Q' is observed, then 'not P' must be true).

Section 4: Thomas Kuhn and Scientific Revolutions

While Popper focused on the logic of discovery (how a theory should be tested), Thomas Kuhn (20th Century) looked at the history of science. In his landmark work, The Structure of Scientific Revolutions (1962), he argued that science does not progress linearly by gradually replacing false theories; instead, it progresses through abrupt, revolutionary shifts.

A. Paradigms and Normal Science

Kuhn introduced the concept of the Paradigm.

  • Definition of Paradigm: A paradigm is the entire framework of assumptions, methods, shared values, and agreed-upon problems that define a scientific community during a specific period. It is the ‘rulebook’ for research.
  • Example: Before Newton, the Ptolemaic (Earth-centered) model was the astronomical paradigm. After Newton, the mechanical, clockwork universe became the paradigm.
  • Normal Science: This is the day-to-day work conducted within a prevailing paradigm. Scientists solve "puzzles" defined by the paradigm. They are not trying to overturn the fundamental rules.
B. Crisis and Revolution

Progress occurs in three stages according to Kuhn:

  1. Normal Science: Steady puzzle-solving under the existing paradigm.
  2. Anomalies and Crisis: Observations or experimental results (anomalies) appear that the current paradigm cannot explain. As anomalies accumulate, the paradigm enters a state of crisis.
  3. Scientific Revolution: A new, competing paradigm emerges (e.g., Quantum Physics replacing Classical Physics). This change is a sudden, non-logical "conversion" driven by historical and social factors, not just pure evidence.
C. Incommensurability

Perhaps Kuhn’s most radical idea is Incommensurability.

  • Definition: Two competing paradigms are incommensurable if they are so fundamentally different that they cannot be objectively compared using a shared set of standards or definitions. They speak different scientific languages.
  • Analogy: Comparing the concept of ‘mass’ in Newtonian physics versus Einsteinian relativity. While they use the same word ("mass"), the fundamental definitions and the conceptual space they occupy are entirely different.
  • Implication: If two paradigms are truly incommensurable, then we cannot say the newer one is objectively "better" or "closer to the truth." We can only say it’s different and more effective at solving the puzzles that led to the crisis.

Did you know? Kuhn’s emphasis on the social, historical, and psychological factors in scientific change challenged the traditional image of scientists as purely objective, logical thinkers.

Key Takeaway: Kuhn suggests that science is not a steady march toward truth but a series of revolutionary periods where one governing framework (paradigm) is replaced by another, often without absolute logical justification for the superiority of the new framework.

Section 5: The Status of Scientific Theories – Realism vs. Anti-Realism

Finally, philosophers ask: When a scientific theory is successful (it predicts things well, like gravity), what does that success tell us about reality itself?

A. Scientific Realism

The Claim: Scientific theories are approximately true descriptions of the unobservable world. The entities posited by successful theories (like electrons, black holes, DNA) actually exist.

  • Core Argument: The "No Miracles Argument" (NMA). It would be a miracle if a scientific theory were highly successful at predicting phenomena unless it were at least approximately true. Success means truth.
B. Scientific Anti-Realism (Instrumentalism)

The Claim: Scientific theories are useful tools or instruments for predicting and controlling observable phenomena, but we should not assume they are literally true descriptions of unobservable reality.

  • Core Argument: The "Pessimistic Meta-Induction" (PMI). History is filled with highly successful scientific theories (like the caloric theory of heat, or the aether theory of light) that were later proven fundamentally false. If past successful theories failed to describe reality, why should we assume current successful theories are true?
Example: The Electron
  • Realist View: Electrons exist; the theory accurately describes a real particle.
  • Anti-Realist View: The concept of the electron is a helpful mathematical tool that allows us to build computers and predict chemical reactions. Whether a tiny particle "really" exists exactly as described is irrelevant; its utility is what matters.

Key Takeaway: Realism says successful science mirrors reality. Anti-Realism says successful science is just a useful tool.

Review and Study Checklist

Essential Concepts for Philosophy of Science:
  • Demarcation Problem: Distinguishing science from pseudoscience.
  • Induction: The logic of generalizing from specific observations (and Hume's challenge to it).
  • Falsificationism (Popper): The requirement that a scientific theory must be testable and potentially provable false.
  • Paradigm (Kuhn): The framework of assumptions governing scientific practice.
  • Incommensurability (Kuhn): The idea that rival paradigms cannot be objectively compared.
  • Realism vs. Anti-Realism: Debate over whether scientific theories describe true reality or are just useful instruments.

Good luck with your studies! Remember, the goal here is not to memorize scientific facts, but to question the philosophical foundations upon which those facts are built.