What is This Thing Called Science?

Chapter 1: Science as Knowledge Derived from the Facts of Experience

Based on Alan F. Chalmers' "What is this thing called science?" (4th Edition, 2013)

Why is science special?

• Because it is based on facts not personal opinions.
• What is the difference between a fact and an opinion?

Slogan: "Science is derived from the facts."

• What does this slogan imply to the general public?
  • Scientific knowledge is objective, secure, and reliable (free from personal bias).
  • Not personal opinion, subjective taste, or speculative imagination.
  • We can disagree on the relative merits of Pink Floyd vs. Radiohead, but there is no room for such variation on Galileo's vs. Einstein's relativity. The facts are presumed to determine the superiority of Einstein.

• Historical Roots (The Empiricists & Positivists):
  • British Empiricists (Locke, Berkeley, Hume): All knowledge should be derived from ideas implanted in the mind via sense perception.
  • Logical Positivists (1920s Vienna Circle): Attempted to formalize the logical relationship between scientific theories and facts.

Empiricism

• Facts are presumed to be claims about the world that can be directly established by a careful, unprejudiced use of the senses (what wee can see, hear or touch).
• If observation of the world is carried out in a careful, unprejudiced way then the facts established in this way will constitute a secure, objective basis for science.
• If the reasoning that takes us from facts to the laws and theories (scientific knowledge) is sound, then the resulting knowledge is securely established and objective.

Taking facts seriously

• Before 17th century the observable facts were not taken seriously as the foundation for knowledge
• Knowledge was based largely on authority, Aristotle and the Bible
  When this authority was challenged by an appeal to experience modern science became possible (e.g. Galileo and free fall)

Three Pillars of the Commonsense View

Three core assumptions of scientific facts are established by observation:

1. Pillar (a): Facts are directly given to careful, unprejudiced observers via the senses.
2. Pillar (b): Facts are prior to and independent of theory.
3. Pillar (c): Facts constitute a firm and reliable foundation for scientific knowledge.

The Spoiler:

"There are problems with each of these claims, at best, can only be accepted in a highly qualified form."

Student Task 1: Deconstructing the Slogan

Format: Small Group Discussion

Prompt:

1. Think of a recent scientific claim you saw in the news (e.g., regarding climate change, dietary health, space exploration, or a new medical treatment).
2. How did the media report represent the "facts"?
3. Did the report assume that these facts are "directly given" and "independent of any theory"?
4. In your small group, discuss how much prior background knowledge was required just to understand what the "facts" were. Be prepared to share your thoughts with the class.

Pillar (a) Under Scrutiny: "Seeing is Believing"

Let us focus on sight (the most heavily used scientific sense).

The Passive Model of Vision (The Camera Analogy):

• Rays of light from an object pass through the eye's lens and form an image on the retina.
• Optic nerves transmit this recording to the brain, which records the information.

Misleading Assumptions of the Passive Model:

1. An observer has direct, unmediated perceptual access to facts about the world.
2. Two normal observers viewing the same object from the same place will see identical things because they receive identical retinal images.

Chalmers' Counter-Thesis:

Visual experiences are not determined solely by the object viewed or the image on the retina; they are heavily mind-dependent.

Retinal Images vs. Perceptual Experiences

"Two normal observers viewing the same object from the same place under the same physical circumstances do not necessarily have identical visual experiences, even though the images on their respective retinas may be virtually identical."

Why Do Perceptions Differ?

Our subjective visual impressions are shaped by:

• Background knowledge and expectations of the observer.
• Prior training and cultural experience.
• Mental state and thematic focus.

Key Philosophical Quote:

"There is more to seeing than meets the eyeball."
— N. R. Hanson, Patterns of Discovery (1958)

Schröder's Staircase (Visual Reversal)

• The Phenomenon: When looking at a line drawing of a staircase, most initially see the upper surface of the stairs. With continued viewing, the perspective suddenly and involuntarily flips to show the stairs from underneath.
• The Lesson: The physical object and the retinal image remain absolutely constant, yet your subjective visual experience changes.

Cultural Differences in Visual Perception

• The Phenomenon: Anthropological experiments with members of certain African tribes (who live in cultures without 2D perspective drawings or staircases) show that they do not see the drawing as a staircase at all.
• The Lesson: Learning to interpret 2D perspective drawings is a culturally acquired skill, not a direct deliverable of human physiology.

• Microscope Observations in Biology

• The Phenomenon: A biology student looking through a microscope at a prepared slide sees only a blur of lines and spots. The instructor sees cell structures dividing.

• The Lesson: Microscopists found no difficulty observing cell division once they were alert to what to look for. The student must learn to become a competent observer.

Case Study: Polanyi's Medical Student

The philosopher Michael Polanyi describes a medical student learning to diagnose pulmonary diseases using chest X-rays:

"At first, the student is completely puzzled. For he can see in the X-ray picture of a chest only the shadows of the heart and ribs, with a few spidery blotches between them. The experts seem to be romancing about figments of their imagination; he can see nothing that they are talking about."

The Transformation:

• After weeks of guided training, looking at many different chest X-rays, and listening to expert commentary, a "tentative understanding dawns."
• Eventually, the student is able to see past the ribs and clearly discern a rich panorama of pathological changes, scars, and infections.
• The Moral: The student has literally entered a new visual world.

Student Task 2: The "Expert Eye" Simulation

Format: Interactive Activity

Student Task:

1. Imagine a layperson and an expert (e.g., a botanist or an astrophysicist) are looking at the image above simultaneously.
2. In your notes, write down three distinct scientific facts about this image that are immediately "visible" to the expert but would remain completely invisible (perceived as random noise, blurs, or weeds) to the layperson.
3. Discuss: Is the expert "interpreting" the visual data differently, or is their actual visual experience different? How does this challenge Pillar (a)?

Pillar (b) Under Scrutiny: Do Facts Precede Theory?

Let us analyze the nature of the "facts" themselves.

Factual Statements vs. Physical Objects

• The world is made of objects (like craters or mountains on the moon).
• However, scientific knowledge is not made of objects; it is made of observation statements (e.g., "The moon has craters and mountains").
• Observation statements are linguistic entities that require words and concepts.

The Evolutionary Case Study: Charles Darwin

• During his voyage on The Beagle, Darwin encountered countless novel plants and animals, experiencing a rich array of novel perceptions.
• The Lesson: He would have made no contribution to science had he left it at private perceptions. He contributed to biology only when he formulated public statements describing these observations to be shared, scrutinized, and tested.

Prior Knowledge as a Prerequisite for Facts

Because facts must be formulated as linguistic statements, they cannot be prior to or independent of theory. They require prior conceptual frameworks.

Example: The Child and the "Apple"

1. A child points to a tennis ball and says "apple."
2. The parent intervenes: explains that a ball is not an apple, demonstrating that you cannot bite it.
3. The child later mistakes a choko for an apple and receives more elaborate conceptual corrections.
4. By the time the child can successfully state "There is an apple present," they have already acquired quite a lot of background knowledge about apples.
5. The Lesson: The factual statement presupposes the knowledge, not the other way around.

Prior Knowledge in Scientific Fact-Gathering

The Botanist and the Ignorant Novice

• The Scenario: A skilled botanist and an untrained novice (like Chalmers) take a field trip into the Australian bush to collect observable facts about native flora.
• The Result: The botanist collects facts that are far more numerous, precise, and scientifically significant than those Chalmers is capable of seeing.
• Why? The botanist possesses an elaborate conceptual scheme of botany. Prior knowledge of botany is a prerequisite for formulating the very statements that make up the factual base.

The Defensible Reconceptualization:

We must distinguish between:

• The conceptual resources needed to formulate observation statements (which are knowledge-dependent).
• The truth or falsity of those statements (which can still be established by direct observation once the concepts are understood).

Guided Observation: Rejecting "The Collection of All Facts"

The Illogical Ideal of Theory-Free Observation:

An extreme view suggests we must collect all facts first, without any prior hypothesis or postulate (A. B. Wolfe, cited in Chalmers).

Why This is Absurd:

How can we establish significant facts through observation if we have no guidance as to what kind of knowledge we are seeking or what problems we are trying to solve?

• Ozone vs. Hair Length:
  • Measuring the ozone concentration in the atmosphere yields relevant scientific facts because it is guided by environmental theory.
  • Measuring the average hair length of youths in Sydney yields "facts" that are completely useless to science because no theory deems them relevant.
  • Conclusion: Our search for relevant facts must be guided by our current state of knowledge.

Student Task 3: Fact or Theory?

Format: Whole-Class Debate

Examine the following three statements. For each statement:

1. Identify the unstated theoretical assumptions or conceptual frameworks an observer must possess to accept this statement as a "simple fact."
2. Debate whether a "pure," completely theory-free observer could ever record these facts.

The Statements:

• Statement 1: "The liquid is boiling at exactly 100°C."
• Statement 2: "This limestone sample contains fossils of ancient marine trilobites."
• Statement 3: "The ammeter needle shows a current of 5.2 Amps flowing through the circuit."

Pillar (c) Under Scrutiny: The Fallibility of Facts

Even if we accept that observation statements can be established, are they a "firm and reliable" foundation?

"Observation statements are as fallible as the presuppositions or background knowledge underlying them."

The Core Principle:

If the knowledge/theory that provides the categories we use to describe our observations is defective, the observation statements themselves will be defective.

Historical Example: "The Fire Ascended"

• The Observation: Ancient and medieval observers watched flames rise into the air and asserted "the fire ascended" as a direct observation statement.
• The Defect: This statement was based on the Aristotelian presupposition that fire has a natural property of seeking its natural place in the heavens. Modern chemistry has completely undermined this category, rendering the "observed fact" false.

Historical Case Study 1: The Stationary Earth

For thousands of years, the immobility of the Earth was regarded as an unshakeable, directly observed fact of experience.

The Direct Observation:

• We do not feel the Earth spinning or moving beneath our feet.
• If you drop a stone from the top of a high tower, it falls straight down, landing directly at the base of the tower.
• If the Earth were moving, wouldn't the tower have swept forward, leaving the stone behind?

The Theoretical Presupposition:

• This secure "fact" rested on the Aristotelian assumption that motion requires a continuous force to sustain it (no concept of inertia).
• The Resolution: Once Galileo developed the concept of inertia (showing that the dropped stone retains the Earth's forward motion), the observation was reinterpreted. The tower-drop no longer serves as a "fact" proving a stationary Earth.

Historical Case Study 2: The Size of Mars and Venus

The Naked-Eye Fact:

• Prior to the 17th century, astronomical observation statements agreed that the apparent sizes of Mars and Venus do not change appreciably during the year.
• This was accepted as a solid fact by both geocentric (Ptolemaic) and early heliocentric (Copernican) astronomers.
• It was a massive problem for Copernican theory, which predicted that Venus should appear up to 40 times larger when closest to Earth.

The Galileo-Telescope Intervention:

• Galileo turned his telescope to the heavens and showed that Mars and Venus do change size dramatically, and Venus exhibits phases like the moon.
• The Scientific Breakthrough: Galileo explained that the naked eye is subject to irradiation—an optical effect where bright, distant light sources appear festooned with sparkling, adventitious rays against dark backgrounds, distorting their true size.
• The Fallibility Revealed: A centuries-old "observed fact" was proven to be an optical illusion corrected by a superior instrument.

Summary: What is the Observational Basis of Science?

Revisiting the Pillars:

• Pillar (a) Rejected: Facts are not directly given to careful observers via the senses. Observation is active, public, and heavily influenced by background knowledge and expectations.
• Pillar (b) Rejected: Facts cannot precede theory. To formulate observation statements, we must already possess a conceptual framework, and our search must be guided by problems.
• Pillar (c) Qualified: Facts do not constitute an infallible foundation. Observation statements are objective but fallible. They can be publicly tested and corrected, but they are subject to being overthrown by technological or theoretical advances.

Looking Ahead to Chapter 2:

If passive observation is so problematic, how does science progress? We must move from passive, private observation to active, public, and practical intervention—in other words, the realm of experimentation.