The Scientific Method

The scientific method of acquiring knowledge is composed of three steps: (1) perceiving via the senses, e.g., observation, to determine facts (empirically true or false statements), where mathematics is sometime used to provide factual precision; (2) using deductive and inductive reasoning to arrive at statements about cause and effect relations among statements so that they can be proved factually true or false; (3) conducting careful experiments (to restrict causes) on statements (called hypotheses at the point of testing for truth or falsity) that can be duplicated by other qualified people to arrive at the same belief (the mental acceptance of a true or false statement) via inductive (probabilistic or statistical) reasoning.   The first two steps are used in common by everyone from child to philosopher and theologian.   It is the third step, used together with the other two, that distinguishes science from non-science.   (Some definitions add more steps, but the necessary ones are the above three.)

Science assumes three axioms.   The most fundamental axiom of the scientific method is that there is a natural world independent of one's perception of it.   To believe otherwise (called "nihilism") would make nonsense of all purported scientific truths.   A second axiom is determinism, the belief that all natural events, including those inside the brain and mind, are caused by previous natural events.   Determinism rejects the belief that natural events are caused by supernatural events, or by nothing at all, so that there is no such thing as "free will"; that is, effects without causes.   In other words, events don't just "happen".   Every effect has an antecedent cause.   However, the scientific method says nothing regarding the truth or falsity of statements about the causes of non-natural (supernatural) events and things, e.g., life after death, eternity, heaven, God, events before the "Big Bang" (the beginning of the universe as humans know it), etc., because statements based on these concepts are untestable (step 3).

A third axiom underlying the scientific method is empiricism, the belief that the most reliable way of knowing the causes of natural events, including human behavior, is to rely on the senses, e.g., observation, and careful sense-experience, called experiments, that can be repeated and corroborated by other qualified persons, i.e., people who are trained to observe and make inferences about natural phenomena.   For example, with respect to the General Theory of Relativity (see below), only a person trained in astronomy and mathematics can understand and verify the evidence for the cause and effect relationships concerning the theory.   In the modern world, experimenters often use devices that extend the range of the senses, such as, thermometers, barometers, oscilloscopes, spectroscopes, spectrographs, microscopes, telescopes, radar, sonar, radio, amplifiers, voltmeters, weighing scales, photographs, etc.   These instruments periodically are tested against standards to assure accuracy.   Sensation (seeing, smelling, tasting, touching, hearing) and their artificial extensions must be corroborated again and again.   No autocratic explanation is acceptable in science.

The be a science, a knowledge acquisition system must meet all of the following 5 conditions:

1. Statements are based on natural laws and natural causation;

2. Statements are explained by natural laws and natural causation;

3. Statements are testable by empirical methods;

4. Statements are falsifiable by empirical methods;

5. Conclusions (empirical truths) are tentative, not dogmatic.

Scientists, like everyone else, also rely on written accounts of other people's senses, experiments and statements because reinventing facts and factual relationships over and over again would be tiresome and futile.   For this to succeed, their language is necessarily as precise and clear as possible, without abstractions that cannot be understood, much less proven, e.g., "Peace is good." (Is this a statement, a definition, a personal preference, or an expression of emotion?)   Periodically, the written statements of scientific truths are resubjected to criticism and experiment to reestablish their validity.   With respect to highly variable human behavior, theories alone don't get one very far in establishing truths.   Only experiments, such as frequent adjustments to welfare, trade, immigration, tax, and stock market regulations, determine workable policies.   With respect to economic and political theories, the results of capitalism, socialism, democracy, autocracy, and other "isms" as practiced at regional or national levels ultimately determine their efficacy.

Determinism and empiricism are supported by the mental process called reasoning, which uses logical deduction and induction to make inferences about the truth or falsity of statements (called "hypotheses" when tested) about natural events.   Determinism and empiricism differ from rationalism, which is the belief that truth can be derived from observation and deductive reasoning alone (steps 1 and 2), a system of acquiring knowledge used by philosophers, theologians and other non-scientists.   It also rejects knowledge based on internal experiences of the mind, called mysticism.   The special value of the scientific method is its success in predicting natural events, including some human behavior, from other natural events through established physical laws that make human life easier and more secure.   Examples are the advances in thermodynamics, nutrition, atomic structure, genetics and medicine.   (When applied by politicians to weapon inventions, they also make human life more miserable.)   The method also satisfies the elemental instinct of homo sapiens to know more about his/her environment.   The scientific proof of the General Theory of Relativity is an example of how the scientific method is used to verify theories.

General theory of relativity (GTR): The gravity of any mass warps the space and time around it.   (Note that this theory has natural causes (gravity) and natural effects (space and time warp).)

There is no direct test of the GTR.   However, there are four deductions from the GTR that can be tested:

1. The orientation of Mercury's orbit is found to precess in space over time.   There are an extra 43 seconds of arc per century in this precession that is predicted by the GTR and observed to occur.

2. The direction of light propagation should be changed in a gravitational field.   Precise observations indicate that the GTR is correct, both about the effect and its magnitude.

3. The GTR predicts that light coming from a strong gravitational field should have its wavelength shifted to larger values (a "redshift").   Detailed observations indicate such a redshift, and its magnitude is correctly given by the GTR.

4. The gravitational field has gravitational waves that carry energy.   They have been observed indirectly in the binary pulsar.   Because the arrival time of pulses from the pulsar can be measured very precisely, it can be determined that the period of the binary system is gradually decreasing.   It is found that the rate of period change (about 75 millionths of a second each year) is what would be expected for energy being lost to gravitational radiation, as predicted by the GTR.

The above example illustrates how deductions from a general statement can be proved inductively by experiment, thereby proving the general statement by inference.   This is how science works in general for other theories, such as Organism Evolution, Atomic Structure, Electromagnetic Field Theory, etc.   A statement is scientific if it has causes and effects that can be tested; that is, subjected to experience (evidence).   If not, then it is a nonscientific one.

A scientist is a person who uses the scientific method to acquire knowledge about natural events.   Scientists do not always arrive at correct causes of these events and they sometime let their prior beliefs, self-interest, and resistance to change interfere with their beliefs about new true statements that contradict old statements thought to be true.   Also, some scientists accept scientific explanations about the causes of some natural events, but accept supernatural causes about other natural events.   In other words, they accept the 3 axioms of science for some events, but not for others.   These alternate beliefs about knowledge are often inner experiences, internalized communal and family beliefs, and divine revelations set down in some tract or book.   Are these alternate ways of knowing natural events, including human behavior, in a person consistent? Are they rational?

Since science relies on inductive reasoning based on mathematical probability and statistics to establish empirically true statements, there are few absolute truths in science, viz., the speed of light in a vacuum.   Instead, its conclusions are usually considered "probable" or "improbable" rather than absolute.   However, when the evidence for truth is overwhelming, scientists for convenience call these extremely probable statements "facts" and "laws", which become the foundations for discovering other probable facts and laws.   Gravitational attraction, atomic and molecular structures, and organism evolution are examples of scientific "facts" and "laws".   In reality, all scientific truths are tentative in an endless search for more accurate knowledge about the causes and effects of natural events, including human behavior, with one explanation continually being replaced by a better one.   For example, the geocentric system of the universe espoused by Hipparchus and Ptolemy in 140 BCE was eventually discarded and replaced by the Copernican heliocentric system of 1543 CE, but not without many years of intolerance, strife and persecution.   As another example, Newton's universal laws of physics were improved by the relativity laws of Einstein.   There is no reason to believe that these "facts" will not be replaced by better ones.   There are no dogmas in science.

Some societies have promoted scientists and the scientific method, while others have ignored the method and persecuted its proponents because certain beliefs based on knowledge acquired through the scientific method conflicted with prevailing non-scientific beliefs.   The countries in which science ultimately was accepted or at least tolerated, augmented by technologies, some of which were derived from science, currently enjoy the highest living standards in the world.   However, science and scientists always have been subjected to criticism and persecution by people who espouse contrary, non-scientific beliefs.   The criticisms remain today.

There have always been scientists, although they were not recognized as such.   The first scientists were the people who domesticated and bred more useful species of plants and animals used as food, clothing and transportation.   They observed, used reason, formed hypotheses, and experimented in crude ways to prove and disprove them over millenia.   There were also ancient physicians, names unknown, who practiced science by applying natural remedies and performing minor operations.   As early as 747 BCE in Mesopotamia, the astronomers who observed the planets and stars to make accurate predictions about eclipses were scientists.   However, for a long time before and after this date, many astronomers attempted to link star, planet, sun, and moon positions to human events in attempts to predict them, a pursuit called astrology.   Astrology is not science, since the predictions based on these hypotheses are not corroborated statistically, only by chance.   Nevertheless, some people today believe in the predictions of astrology and phrenology, as well as the explanations of creationism and intelligent design for how the universe works.   All of these methods are nonsciences (pseudosciences, when claiming to be "science").

Before the scientific method became prevalent in areas other than astronomy, philosophers, who are rationalist thinkers, attempted to determine natural truths.   In 580 BCE, Thales, a Greek philosopher, speculated that all matter was made of water or modified water.   Although his conclusions were wrong, they represent the first recorded rationalist belief about the natural world; that is, explanations of things dependent on other natural things, but without experiment, the all-important 3rd step of the scientific method.   In 440 BCE, the Greek philosopher, Leucippus, speculated that all matter was composed of elementary particles he called atoms, a truth, with modification, that would be corroborated by science much later.   In 350 BCE, Aristotle, a Greek philosopher, suggested an alternate view of matter: The world was made up of four elementary units - earth, water, air and fire.   He added that the heavens were made up of a fifth element he called aether ("blazing", in reference to the luminous stars).   We now know that all these views are non-scientific and incorrect, but the Greek philosophers popularized thinking about the natural world that led to eventual application of more scientific methodology.   Therefore, classical Greek thinking, with few exceptions (Eratosthenes of Cyrene (275-194 B.C.), when he accurately measured the circumference of the earth), was not scientific, but is often referred to as the "cradle of science" because it began objective thinking about our world rather than assume it was explained adequately by prevailing nonscientific methods.

Alchemy, practiced by the Chinese, Egyptians, and Arabs since prehistoric times was part science and part mysticism.   It was brought to Spain and Sicily by the Arabs during their conquests and eventually was practiced throughout Europe.   However, when alchemy failed to produce precious metals from base metals and was used by charlatans to cheat people of valuables, it fell into disrepute in medieval Europe in the 13th and 14th centuries.   Thereafter, alchemy slowly evolved into chemistry and physics, but persisted into the 18th century alongside science.   Paracelsus (1493-1541), a Swiss physician and alchemist, is the first person known to have made a switch from alchemy to chemistry when he decided that making medicines to conquer disease was a more productive pursuit.   The scientific contributions of the alchemists were strong acids, in particular sulfuric acid, which has been the most important industrial chemical for centuries.

The English friar and philosopher, Roger Bacon, a physician and alchemist, impressed by muslim science and alchemy, which soon would be suppressed by muslim theologians, promoted the scientific method in his works Opus Majus and Opus Minus in 1267, and Opus Tertium in 1268, in which he stressed observation, hypothesis, and experimentation in contrast to scholars who used pure reasoning to arrive at truths, an approach called scholasticism in medieval times.   When he lost his superior's support, he was imprisoned in 1279 and forced to repent his views.

Astronomy eventually shed astrology and became fully scientific during the Middle Ages.   Copernicus, a Polish astronomer, presented a compelling case for a heliocentric system that was published in 1543 CE, near his death, when he could not be persecuted by religious authorities, a theory he formulated much earlier.   By postulating an alternate world system against the prevailing Ptolemaic geocentric system, it explained star and planet movements more simply and inadvertently promoted the radical and humbling view that the earth and the humans who live on it are not at the center of the universe, but merely a small part of it on the fringes.   Another important science promoter was the English philosopher, Francis Bacon, who in 1629 published Novum Organum, which argued for the efficacy of the scientific method to establish truths rather than the purely deductive logical and mathematical (i.e., rationalist) approaches.

Over many centuries, many men and a few women used the scientific method to arrive at important conclusions about our world.   Their successes improved living conditions and promoted other people to use the scientific method.   Pythagoras (582-497 BCE), the Greek philosopher and mathematician (he gave us the Pythagorean Theorem), was the first scientist of whom we know.   He founded acoustics by relating the pitch of sound to the length and tension of of musical strings, relationships that are valid today.   Another Greek, Archimedes (287-212 BCE), worked out the principles of buoyancy and the lever, and invented the screw pump.

Abu Musa Jabir Ibn Hayyan (Geber, in Latin, 780-850 CE), an Arabian alchemist, published accurate chemical experiments describing amonium chloride, white lead, nitric acid and strong acetic acid by distillation.   He also described the making of dyes and varnishes and metal refining.   Abu-Bakr Muhammad Ibn Zakariyya Ar-Razi (Rhazes, in Latin, 860-930), a Persian physician and alchemist, differentiated smallpox from measles, prepared Plaster of Paris to set broken bones, and studied the properties of antimony.   Arnold of Villanova (1235-1311), a Catalan alchemist, discovered carbon monoxide (CO), the poisonous gas given off from burning wood with an insufficient amount of air.   He also was the first known person to prepare pure alcohol.

The Italian Renaissance around the beginning of the 13th century featured authors like Dante, Petrarch and Boccacio, who concerned themselves with the everyday lives of people rather than those of the heavens and Gods.   This renaissance spread to other parts of Europe and inadvertenty promoted scientific studies of natural phenomena by its concerns with life on earth rather than in the world beyond.   Mondino De' Luzzi (1275-1326) published more accurate studies of human anatomy.   William of Ockham (1280-1349), an English scholar, argued for reason against faith and earthly objects against Plato's universals.   Leonardo da Vinci (1452-1518) discovered inertia and the acceleration of falling bodies, described human anatomy in great detail and wrote a thesis on flight.   Agricola (1494-1555), a German physician, wrote a classic book on mining, De Re Metallica, to become the first minerologist.   Vesalius (1514-1564), a Flemish anatomist, wrote the first accurate book on anatomy, De Corporis Humani Fabrica.

Galileo (1564-1642), the famous Italian astronomer and physicist, was the archtypical experimenter, always searching for the crucial experiment to prove his hypotheses.   He corrected Aristotelian notions about force, mass and acceleration and used the newly invented telescope to more accurately describe the sun, moon and planets to found mechanics.   The suppression of his ideas by theologians is a story well known.   Thus, scientists came from many regions of the globe, but were suppressed in some places by vested interests, as they are today.

From prehistoric times to the present day, scientists continue to describe a more realistically convincing picture of our natural world, including human behavior, than other epistemological methods.   Statements that may be subjected to experiment are therefore more likely to be prove true or false than proofs based on authority and speculation.