A brief history of scientific practice

by Anthony Carpi, Ph.D., Anne E. Egger, Ph.D.

This material is excerpted from a teaching module on the Visionlearning website, to view this material in context, please visit Research Methods: The Practice of Science.

The recorded roots of formal scientific research lie in the collective work of a number of individuals in ancient Greek, Persian, Indian, Chinese, and European cultures, rather than from a single person or event. The Greek mathematician Pythagoras is regarded as the first person to promote a scientific hypothesis when, based on his descriptive study of the movement of stars in the sky in the 5th century BCE, he proposed that the Earth was round. The Indian mathematician and astronomer Aryabhata used descriptive records regarding the movement of objects in the night sky to propose in the 6th century CE that the Sun was the center of the solar system. In the 9th century, Chinese alchemists invented gunpowder while performing experiments attempting to make gold from other substances. And the Persian scientist Alhazen is credited with devising the concept of the scientific experiment while researching properties related to vision and light around 1,000 CE.

These and other events demonstrate that a scientific approach to addressing questions about the natural world has long been present in many cultures. The roots of modern scientific research methods, however, are considered by many historians to lie in the Scientific Revolution that occurred in Europe in the 16th and 17th centuries. Most historians cite the beginning of the Scientific Revolution as the publication of De Revolutionibus Orbium Coelestium (On the Revolutions of the Heavenly Spheres) in 1543 by the Polish astronomer Nicolaus Copernicus. Copernicus's careful observation and description of the movement of planets in relation to the Earth led him to hypothesize that the Sun was the center of the solar system and the planets revolved around the Sun in progressively larger orbits in the following order: Mercury, Venus, Earth, Mars, Jupiter, and Saturn (Figure 1). Though Copernicus was not the first person to propose a heliocentric view of the solar system, his systematic gathering of data provided a rigorous argument that challenged the commonly held belief that the Earth was the center of the universe.

De revolutionibus orbium coelestium combined
Figure 1: The front cover and an inner page from De Revolutionibus showing Copernicus's hypothesis regarding the revolution of planets around the sun (from the 2nd edition, Basel, 1566). (from http://www.webexhibits.org/calendars/year-text-Copernicus.html)

The Scientific Revolution was subsequently fueled by the work of Galileo Galilei, Johannes Kepler, Isaac Newton, and others, who not only challenged the traditional geocentric view of the universe, but explicitly rejected the older philosophical approaches to natural science popularized by Aristotle. A key event marking the rejection of the philosophical method was the publication of Novum Organum: New Directions Concerning the Interpretation of Nature by Francis Bacon in 1620. Bacon was not a scientist, but rather an English philosopher and essayist, and Novum is a work on logic. In it, Bacon presented an inductive method of reasoning that he argued was superior to the philosophical approach of Aristotle. The Baconian method involved a repeating cycle of observation, hypothesis, experimentation, and the need for independent verification. Bacon's work championed a method that was objective, logical and empirical, and provided a basis for the development of scientific research methodology.

Figure 2: Sir Isaac Newton

Bacon's method of scientific reasoning was further refined by the publication of Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy) by the English physicist and mathematician Isaac Newton in 1686. Principia established four rules (described in more detail here) that have become the basis of modern approaches to science. In brief, Newton's rules proposed that the simplest explanation of natural phenomena is often the best, countering the practice that was common in his day of assigning complicated explanations derived from belief systems, the occult, and observations of natural events. And Principia maintained that special explanations of new data should not be used when a reasonable explanation already exists, specifically criticizing the tendency of many of Newton's contemporaries to embellish the significance of their findings with exotic new explanations.

Bacon and Newton laid the foundation that has been built upon by modern scientists and researchers in developing a rigorous methodology for investigating natural phenomena. In particular, the English statisticians Karl Pearson and Ronald Fisher significantly refined scientific research in the 20th century by developing statistical techniques for data analysis and research design (see our Data: Statistics module). And the practice of science continues to evolve today, as new tools and technologies become available and our knowledge about the natural world grows. The practice of science is commonly misrepresented as a simple, four- or five-step path to answering a scientific question, called "The Scientific Method." In reality, scientists rarely follow such a straightforward path through their research. Instead, scientific research includes many possible paths, not all of which lead to unequivocal answers. The real scientific method, or practice of science, is much more dynamic and interesting.

Anthony Carpi, Ph.D., Anne E. Egger, Ph.D. “A brief history of scientific practice” Visionlearning Vol. HID (1), 2009.