6. Experience in Science and the Concept of Nature

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Lecture Notes

Main Topics #

Common Experience vs. Private Experience #

• Common experience: universal human experience that cannot be avoided (e.g., observing growth, motion, change)
• Private experience: specific to individuals or groups, often requiring special effort, training, or instruments
• All humans share common experience; not all have private experience
• This distinction explains the division of labor in experimental science

The Division of Labor in Experimental Science #

• Theoretical physicists rely on empirical physicists’ experiments and observations
• Modern scientists must sometimes believe others’ empirical findings they could not have conducted themselves
• Example: Louis de Broglie’s wave mechanics was tested at Bell Telephone Laboratories in New York, not by de Broglie himself
• Philosophy of nature requires no such division of labor because its subject matter (common experience) is universally accessible
• Paradoxically, experimental science requires more human belief than philosophy does

Heisenberg on the Experimental Method #

• Since Galileo, experiment is the fundamental method of natural science
• Experiments enable passage from general experience to specific experience
• Experiments artificially arrange circumstances to reveal what would not occur in ordinary nature
• The experiment singles out characteristic events in nature to state its laws more directly

Nature’s Etymology and Fundamental Meanings #

• The Greek word φύσις (phusis) and Latin natura derive from the root meaning birth or being born
• Related English words preserve this root: prenatal, postnatal, nativity, native
• The English word “nature” obscures this etymological connection
• First meaning: birth itself—what emerges from within
• Second meaning: the source of birth within the mother; the principle from which birth comes
• Third meaning: any intrinsic source of change (generalizes the second meaning)
• Fourth meaning: what a thing is; its essence (too general to define natural philosophy alone)
• The idea of being within and therefore hidden persists across all meanings
• This explains Heraclitus’s dictum: “Nature loves to hide” because what is within is hidden

Heraclitus and the Hiddenness of Nature #

• Nature’s hiddenness is not mysterious—it simply reflects that internal principles are not immediately visible
• We know nature through its effects (motion and rest), not by direct observation of the principle itself
• The internal disposition of a thing (e.g., “the native act and figure of my heart” in Shakespeare) is hidden even to ourselves

Theology and Common Experience #

• Pope Paul VI (Mysterium Fidei) argues that theological definitions use concepts tied to “universal and necessary experience”
• Universal experience = common to all humans
• Necessary experience = cannot be avoided
• Theological formulas express what the human mind grasps through common experience
• Theology primarily employs the via negativa (negative way), knowing God by negation
• When negating, understanding the general is more important than understanding the particular
• Therefore theology relies heavily on knowledge grounded in common experience
• Thomas Aquinas’s access to Aristotle’s natural philosophy was essential for developing systematic theology

Aristotle’s Definition of Nature: Preliminary Distinctions #

• Nature is distinguished from art (human making)
• Things that are by nature include: animals, their parts, plants, and simple bodies (earth, fire, air, water)
• Things that are by art include: beds, clothing, tools, and other artificial objects
• Natural things have intrinsic causes of motion and rest
• Artificial things have their causes external to themselves
• The order of examples given (animals → plants → simple bodies) reflects increasing distance from the paradigm of nature (living things)

Natural Things and Intrinsic Causality #

• Natural things have within themselves a cause of change (motion, growth, decay, alteration)
• They also have within themselves a cause of rest or limitation
• A tree grows to a certain height and then stops—this is due to something within the tree, not external
• A piece of wood burns in fire; a stone resists burning in fire—not because of their forms (chair vs. bench) but due to the nature of the materials
• External conditions (sun, rain, soil, fire) are identical for different natural things, yet they behave differently
• This difference must be due to something intrinsic to each thing

Distinguishing Nature from Custom #

• Custom is sometimes called “second nature” because it becomes internalized
• However, custom is acquired, not intrinsic from the start
• Nature is first—the primary cause of a thing’s behavior
• When I fall from a window, it’s due to my nature as a body heavier than air, not my nature as human
• When I climb stairs, it’s due to my nature as an animal with muscles and will
• This distinction between what is first and what is secondary is crucial

Shakespeare on Nature and Misuse #

• In Romeo and Juliet, Friar Lawrence speaks of things departing from their “true birth” (true nature)
• “Revolts from true birth, stumbling on abuse” describes moral disorder
• All our parts are beautiful if used according to their nature (“fair use”)
• Misuse comes from straining parts away from their proper function
• Understanding nature is essential to ethics

The Methodological Importance of Common Experience for Philosophy #

• Philosophy of nature is based entirely on common experience
• Every human has access to the same experiential data about growth, change, motion, and rest
• This universality allows philosophy to proceed without special instruments or training
• In contrast, experimental science requires division of labor and specialized equipment

Key Arguments #

Why Natural Things Must Have Intrinsic Causes #

1. Different natural things in identical external conditions behave differently
2. A tree grows while a nearby stone does not
3. The external conditions (sun, rain, soil) are the same
4. Therefore, the difference must be due to something within each thing
5. This internal difference is what we call nature

Why Theology Depends on Common Experience #

1. God is known primarily via negativa (by negation)
2. Negating requires understanding what is negated
3. Understanding the general is more useful than understanding the particular when negating
4. For example: negating “God has parts” is more powerful than negating “God has 2 atoms of hydrogen and 1 of oxygen”
5. Therefore, we must understand general concepts tied to universal human experience
6. These general concepts come from common experience
7. Hence theology fundamentally depends on knowledge grounded in common experience

Why Experimental Science Requires Belief #

1. Private experience is not universally shared
2. Theoretical physicists cannot conduct all experiments themselves
3. They must believe empirical physicists’ reports of observations
4. Philosophy of nature requires no such belief because its data (common experience) is universally available
5. This makes experimental science more dependent on human belief than natural philosophy

Important Definitions #

• φύσις/natura: An intrinsic principle; fundamentally means birth or what is born; the source of motion and rest within a thing
• Common experience: Universal human experience that all humans share and cannot avoid (e.g., observing growth, motion, pleasure, pain)
• Private experience: Experience specific to some individuals or groups, often requiring special training, effort, or instruments
• Via negativa (negative way): Knowing God by negation, stating what He is not rather than what He is
• Via affirmativa (affirmative way): Knowing by affirmation; more effective when affirming the particular rather than the general
• Natural things: Things whose cause of motion and rest is intrinsic (within) themselves
• Artificial things: Things whose cause of motion and rest is external (imposed by art or human making)
• Universal and necessary experience: Experience common to all humans that cannot be avoided (Pope Paul VI’s term for common experience)

Examples & Illustrations #

The Tree and the Stone #

• Same sun, rain, and soil affect both
• Tree grows; stone does not
• Difference is intrinsic, not due to external conditions
• Demonstrates that nature is within things

The Wooden Chair and Stone Bench in Fire #

• Both placed in identical fire
• Wooden chair burns; stone bench resists
• Not because being a chair or bench, but due to the wood vs. stone’s intrinsic nature
• Shows that form is external; material nature is internal
• A boy’s mother answers: “It’s the nature of wood to burn, but not of stone”

The CIA Test (Movie) #

• Candidates arrive at a countryside estate for testing
• Told to relax while testers are delayed
• Unknown to them, testing is already occurring—observing character through artificial circumstances
• Shows how arranging artificial situations reveals what is normally hidden
• Demonstrates the method of experimentation: creating unnatural circumstances to test character or nature

The Party Hypothetical (Millionaire’s Proposition) #

• Man asks woman: “Would you sleep with a man for a million dollars?”
• Woman hypothetically says yes
• Later the man offers $20
• Woman protests: “Who do you think I am?”
• Man replies: “We know what you are. We’re just haggling about the price.”
• The hypothetical question artificially arranged circumstances, revealing character not visible in normal circumstances

Shakespeare’s “All’s Well That Ends Well” - Parolles #

• Parolles (meaning “words” in French) brags about his bravery
• Soldiers dress as enemies, capture him, threaten him
• He betrays his troops under duress
• When his mask is removed, he is disgraced
• Shakespeare: “Who cannot be betrayed with a plot?”
• Shows how artificial circumstances test and reveal the hidden nature of character

Wine Fermentation #

• Natural wine ferments to 11-15% alcohol naturally, then stops
• Fortified wine has brandy added to reach 18-20% alcohol
• The stopping point in natural wine shows intrinsic nature at work
• Wine has an internal limit to its fermentation—a cause of rest within it

Aristotle’s Example of the Doctor Curing Himself #

• A doctor with a disease uses medical art to cure himself
• Art (medical knowledge) is within the thing changed (the doctor’s body)
• Yet this is still art, not nature, because the art and disease happen to be in the same person
• The art does not belong to curing “as such”—it belongs “by happening” (accidentally)
• Illustrates why “as such, not by happening” is necessary in the definition of nature

Falling from a Window #

• I fall because I am heavier than air (my nature as a body)
• Not because I am human or animal
• If I were made of helium, I would rise
• My “first” nature is what is primarily responsible, not my secondary characteristics

The Kitten and the Nipple #

• Each kitten consistently goes to the same nipple
• Without this internal ordering from nature, chaos would result
• Shows that nature provides intrinsic organization and limits

Notable Quotes #

“Nature loves to hide” — Heraclitus

“For not so vile that on the earth doth live, but to the earth some special good doth give… Revolts from true birth, stumbling on abuse” — Shakespeare, Romeo and Juliet (Friar Lawrence)

“Since the time of Galileo, the fundamental method of natural science had been the experiment” — Werner Heisenberg, Gifford Lectures

“This method made it possible to pass from general experience to specific experience” — Heisenberg on the experimental method

“One can never note a likeness of the creature to God without at the same time noticing a greater unlikeness” — Fourth Lateran Council, cited by Pope Paul VI

“I am the way, the truth, and the life” — Christ in Gospel of John (using ὁδός/hodas—the road/way)

“For these formulae are expressed concepts which are not tied to one specific form of human civilization, nor a definite period of scientific progress, nor one school of theological thought. But they present what the human mind, by universal and necessary experience, grasps as realities.” — Pope Paul VI, Mysterium Fidei

Questions Addressed #

Why does belief play a larger role in experimental science than in philosophy of nature? #

• Philosophy of nature relies on common experience universally shared by all humans
• Experimental science creates private experience requiring specialized equipment and training
• Most scientists cannot replicate all experiments they study; they must believe colleagues’ reports
• This creates a division of labor and dependency on human testimony
• Philosophy avoids this because its data is universally available

How can nature be hidden if we are supposed to study it? #

• Nature is known through its effects (motion and rest), not by direct vision of the principle itself
• We infer nature from the difference between things in identical external conditions
• Reason, working from common experience, enables understanding of hidden internal principles
• This is the proper method of natural philosophy

How does understanding common experience ground theological knowledge? #

• Theology knows God primarily via negativa (by negation)
• Effective negation requires understanding the general concept being negated
• General concepts come from common human experience
• For example: to say “God is unchanging,” I must first understand change in general from common experience
• Therefore, grounding theology in universal, necessary experience is essential
• This explains why Thomas Aquinas needed Aristotle’s natural philosophy to develop his theology

Why does Aristotle introduce nature by first distinguishing natural from artificial things? #

• Nature must be defined against something—namely, against art
• This clarifies what is distinctive about natural things: intrinsic causality
• Artificial things reveal what natural things are not: their causes are external
• The distinction helps us understand that nature is an internal principle

Why is the distinction between “as such” (per se) and “by happening” (per accidens) important? #

• The example of the doctor curing himself shows that having art within something does not make it nature
• The doctor’s art happens to be in him, but art is not his nature
• Similarly, a tree growing near human artifacts grows by its nature, not by art, even though art is present nearby
• This distinction completes the definition and prevents confusion

How does the etymology of “nature” (phusis/natura = birth) guide understanding of the concept? #

• Birth is something that emerges from within and is therefore hidden
• This explains why nature “loves to hide”
• All derived meanings retain the idea of something internal
• Nature is not external appearance but internal principle
• This helps students grasp why we cannot see nature directly but only its effects