Inductive reasoning comes to science

Francis Bacon, no particular relation to Roger, is credited with introducing inductive reasoning into scientific inquiry in the 17th century. A distinguished member of the English aristocracy during the reigns of Elizabeth I and James I, his life was a checkered affair that included a destructive corruption scandal.

However, as the 20th-century writer and anthropologist Loren Eiseley put it, Bacon, "more fully than any man of his time, entertained the idea of the universe as a problem to be solved...."

Francis Bacon

Francis Bacon

Bacon was a philosopher, and he sought to resolve the problems that Aristotle's deductive approach to creation presented, such as the fact that Aristotle decreed that the world conformed to his construction of it, rather than vice versa.

Not only that, but most medieval thinkers had swallowed Aristotle whole, and regurgitated his ideas, which were often not even close to being correct. Bacon was frustrated by the obsolete and often clearly erroneous view of the world most of his contemporaries held.

He sought to bring a whole new approach to philosophy and science. And so he did. While many others built on his ideas, Bacon accomplished something truly revolutionary.

Inductive reasoning begins with specific details and observations — of natural occurrences or behavior, say — and uses them to arrive at a principle to explain them. What we now call the scientific method is largely inductive.

Deductive reasoning moves from the general to the specific. It uses logic to confirm something we already know to be true. Deduction is vulnerable to error at every step because it accepts the truth of the elements it uses to establish new truths.

Roger Bacon

Was Roger Bacon Europe's first real scientist?

This 13th-century English monk recognized that going to the source of phenomena was the surest way to understand them.

Roger Bacon

Statue of Roger Bacon at Oxford

Bacon was born in Ilchester, in Somerset, around the time King John granted the English nobles some important rights in the Magna Carta of 1215. Education was apparently an important value in his family, and he went to Oxford University probably at about age 13.

Bacon lectured at the University of Paris and pursued a life of dogged intellectual inquiry at a time when unorthodox opinions were dangerous — even fatal. At about the age of 40, he became a Franciscan friar, which limited his ability to publish his works, as any writings had to be approved by his order.

About 10 years later, though, his friend Guy le Gros de Foulques became Pope Clement IV. During the few years of Clement's reign, Bacon published his Opus Maius, about science and theology, and other works.

Bacon understood that mathematics was crucial to understanding science. He refused to accept received knowledge without testing out its tenets with experiments — and at the time, the scholarly world was all about received knowledge from the ancients.

He created the first useful maps in hundreds of years by re-introducing map projections, he was a pioneer in the field of optics, and he began a reformation of the calendar that was adopted hundreds of years later by Pope Gregory XIII.

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Spontaneous generation and Francesco Redi

Some small organisms are visible to the eye, at least in large numbers. Thousands of years ago, people came up with an explanation for the sudden appearance of mold on bread, maggots on meat, mice in grain: The creatures came to life spontaneously in decaying organic matter.

The theory of spontaneous generation — the belief that under the right circumstances living organisms could come into being without parents — was the target of perhaps the first real scientific experiment, in 1668.

That was the year that the Italian physician Francesco Redi set out to prove his idea that maggots came from eggs laid by flies. This was no fluke: Redi was an intellectual who belonged to prestigious literary societies and undertook many experiments over the course of his life.

Francesco Redi
Francesco Redi

He had also been a member of the Accademia del Cimento, an early scientific society founded by the Medicis in Florence.

Redi set out three groups of jars containing rotting meat. One group he closed completely, one he covered with gauze, and one he left completely open.

As time went on, flies enter the uncovered jars. They landed on the gauze on the partially covered jars. However, there were no flies around the totally covered jars.

Later, many maggots appeared on the meat in uncovered jars. A few maggots appeared on the meat in the partially covered jars. No maggots showed up on the meat in the totally covered jars.

Redi's use of several jars for each situation showed that his results could be replicated, an important aspect of any scientific experiment.

Redi had proved that flies had to be present on or around the meat for maggots to generate. His work began to raise doubts about spontaneous generation, though it was a long time before it was truly put to rest.

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Pitti Palace, incubator of the scientific method

By 1657, the plague was largely spent and the Catholic Church was becoming a little choosier about its battles, especially given the spread of the Protestant Reformation.

In Italy, the Renaissance was winding down. Science had become so intrinsic to intellectual life that Leopoldo De' Medici, who was both a prince and, later, a Catholic cardinal, opened his private chambers in the Pitti Palace in Florence to a new scientific academy, the  Accademia del Cimento. ("Cimento" means "trial.")

Lion from the Pitti Palace
Lion from the Pitti Palace

Leopoldo and his brother, Grand Duke Ferdinando II of Tuscany, founded, and funded, the academy, which would meet for just 10 years. Its influence would last much longer.

Ferdinando had supported Galileo's experiments and had tried unsuccessfully to nudge the Church toward accepting them in the spirit of exploration. In the 1640s, he opened the Boboli Garden, the grounds of the Pitti Palace, his official residence, to experiments with thermometers, poultry incubators and other instruments.

Galileo's spirit hovered over the academy. Its motto was "provando e riprovando" — "testing and re-testing." Founding members included Galileo's students, like Vincenzo Viviani, who with fellow academy member Giovanni Alfonso Borelli, worked on experiments to pin down the speed of sound waves.

Another member was the physician Francesco Redi, who performed what is considered the first scientific experiment.

Distractions to the patrons, and quarrels among the members, doomed the academy. Its last act was the publication of a compilation of members' work, Examples of Natural Experiments, which in its Latin translation influenced the European scientific community profoundly, becoming essentially the science textbook for at least 100 years.

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