---
title: "Science in the Renaissance"
chunk: 2/3
source: "https://en.wikipedia.org/wiki/Science_in_the_Renaissance"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T03:40:19.278771+00:00"
instance: "kb-cron"
---

While differing in some respects, alchemy and chemistry often had similar goals during the Renaissance period, and together they are sometimes referred to as chymistry. Alchemy is the study of the transmutation of materials through obscure processes. Although it is often viewed as a pseudoscientific endeavor, many of its practitioners utilized widely accepted scientific theories of their times to formulate hypotheses about the constituents of matter and the ways matter could be changed. One of the main aims of alchemists was to find a method of creating gold and other precious metals from the transmutation of base materials. A common belief of alchemists was that there is an essential substance from which all other substances formed, and that if you could reduce a substance to this original material, you could then construct it into another substance, like lead to gold. Medieval alchemists worked with two main elements or "principles", sulphur and mercury.
Paracelsus was a chymist and physician of the Renaissance period who believed that, in addition to sulphur and mercury, salt served as one of the primary alchemical principles from which everything else was made. Paracelsus was also instrumental in helping to put chemical practices to practical medicinal use through a recognition that the body operates through processes which may be seen as chemical in nature. These lines of thinking directly conflicted with many long-held traditional beliefs, such as those popularized by Aristotle; however, Paracelsus was insistent that questioning principles of nature was essential to continue the general growth of knowledge.
Despite its frequent basis in what may be considered scientific practices by modern standards, numerous factors caused chymistry as a discipline to remain separate from general academia until near the end of the Renaissance, when it finally began appearing as a portion of some university education. The commercial nature of chymistry at the time, along with the lack of classical basis for the practice, were some of the contributing factors which led to the general view of the discipline as a craft rather than a respectable academic discipline.

=== Astronomy ===

The astronomy of the late Middle Ages was based on the geocentric model described by Claudius Ptolemy in antiquity. Probably very few practicing astronomers or astrologers actually read Ptolemy's Almagest, which had been translated into Latin by Gerard of Cremona in the 12th century. Instead they relied on introductions to the Ptolemaic system such as the De sphaera mundi of Johannes de Sacrobosco and the genre of textbooks known as Theorica planetarum. For the task of predicting planetary motions they turned to the Alfonsine tables, a set of astronomical tables based on the Almagest models but incorporating some later modifications, mainly the trepidation model attributed to Thabit ibn Qurra. Contrary to popular belief, astronomers of the Middle Ages and Renaissance did not resort to "epicycles on epicycles" in order to correct the original Ptolemaic models—until one comes to Copernicus himself.
Sometime around 1450, mathematician Georg Purbach (1423–1461) began a series of lectures on astronomy at the University of Vienna. Regiomontanus (1436–1476), who was then one of his students, collected his notes on the lecture and later published them as Theoricae novae planetarum in the 1470s. This "New Theorica" replaced the older theorica as the textbook of advanced astronomy. Purbach also began to prepare a summary and commentary on the Almagest. He died after completing only six books, however, and Regiomontanus continued the task, consulting a Greek manuscript brought from Constantinople by Cardinal Bessarion. When it was published in 1496, the Epitome of the Almagest made the highest levels of Ptolemaic astronomy widely accessible to many European astronomers for the first time.

The last major event in Renaissance astronomy was the work of Nicolaus Copernicus (1473–1543). He was among the first generation of astronomers to be trained with the Theoricae novae and the Epitome. Shortly before 1514 he began to revive Aristarchus's idea that the Earth revolves around the Sun. He spent the rest of his life attempting a mathematical proof of heliocentrism. In De revolutionibus orbium coelestium, published in 1543, Copernicus attempted to align his work as closely as possible with Ptolemaic tradition. A comparison of his work with the Almagest shows that he followed Ptolemy's methods and even his order of presentation. Yet, in order to purge astronomy of the equant—which violated the theological and philosophical ideal that all celestial motion must be perfect and uniform—Copernicus challenged Ptolemy's geocentrism, an orthodoxy that had prevailed for over a millennium. Copernicus' heliostatic model (with a stationary Sun located near, though not precisely at, the mathematical center of the heavens) retained several false Ptolemaic assumptions such as the planets' circular orbits, epicycles, and uniform speeds, but also included such accurate ideas as:

The Earth is one of several planets revolving around the Sun in a determined order.
The Earth rotates daily on its axis and revolves annually about the Sun.
Retrograde motion of the planets is explained by the Earth's motion.
The distance from the Earth to the Sun is small compared to the distance from the Sun to the stars.

=== Mathematics ===