Bacon and Descartes differed in their methods, however. Bacon stressed experimentation and observation. He wanted science to make life better for people by leading to practical technologies. Descartes emphasized human reasoning as the best road to understanding. His Discourse on Method explains how he decided to discard all traditional authorities and search for provable knowledge. Left only with doubt, he concluded that doubt was the only thing he could not question, and that in order to doubt he had to exist as a rational, thinking being. At that point, he made his famous statement, “I think, therefore I am.”

A Step-By-Step Process

Over time, the scientific method evolved into a step-by-step process of discovery. Scientists collected and accurately measured data. To explain the data, scientists used reasoning to propose a logical hypothesis, or possible explanation. They then tested the hypothesis with further observation or experimentation.

For the first time, mathematical calculations were used to convert the observations and experiments into scientific laws. After reaching a conclusion, scientists repeated their work at least once—and usually many times—to confirm and refine their hypotheses or formulate better ones.

Thinkers like Bacon and Descartes helped bring the scientific method to the pursuit of all knowledge. Their pioneering approaches to thought opened the way to even more revolutionary ways of thinking in the 1700s.

Breakthroughs in Medicine and Chemistry

The 1500s and 1600s saw dramatic changes in many of the sciences, especially medicine and chemistry. Like Copernicus, Bacon, and Descartes, scientists rejected long-held assumptions. They relied on new technology, such as the microscope, and benefited from better communication, especially the availability of printed books.

Exploring Human Anatomy

Medieval physicians relied on the works of the ancient Greek physician Galen. Galen, however, had made many errors, in part because he had limited knowledge of human anatomy. During the Renaissance, physicians made new efforts to study the human body.

Infographic titled the scientific method.
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Analyze Information

The scientific method, still used today, is based on careful observation and measurement of data. Why do you think it's critical to follow each step in sequence and to follow the same procedure for each step?


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Table of Contents

World History Topic 1 Origins of Civilization (Prehistory–300 B.C.) Topic 2 The Ancient Middle East and Egypt (3200 B.C.–500 B.C.) Topic 3 Ancient India and China (2600 B.C.–A.D. 550) Topic 4 The Americas (Prehistory–A.D. 1570) Topic 5 Ancient Greece (1750 B.C.–133 B.C.) Topic 6 Ancient Rome and the Origins of Christianity (509 B.C.-A.D. 476) Topic 7 Medieval Christian Europe (330–1450) Topic 8 The Muslim World and Africa (730 B.C.-A.D. 1500) Topic 9 Civilizations of Asia (500–1650) Topic 10 The Renaissance and Reformation (1300–1650) Topic 11 New Global Connections (1415–1796) Topic 12 Absolutism and Revolution Topic 13 The Industrial Revolution Topic 14 Nationalism and the Spread of Democracy (1790–1914) Topic 15 The Age of Imperialism (1800–1914) Topic 16 World War I and the Russian Revolution (1914–1924) Topic 17 The World Between the Wars (1910–1939) Topic 18 World War II (1930–1945) Topic 19 The Cold War Era (1945–1991) Topic 20 New Nations Emerge (1945–Present) Topic 21 The World Today (1980-Present) United States Constitution Primary Sources 21st Century Skills Atlas Glossary Index Acknowledgments