Toruń Logic Group: Logica Copernicana Seminar
About the seminar
Logica Copernicana is an irregular, international seminar devoted to the presentation of advanced research in logic or related to logic. Papers at the seminar will be presented by guests of the Department of Logic or members of the team.
The name Logica Copernicana deliberately refers to the most outstanding scientist from Toruń, Nicolaus Copernicus, who, without a doubt, consciously concluded in his astronomical considerations using some rules of inference,
perhaps even the rules of paraconsistent logic.
The name Logica Copernicana was suggested by our first referent, Walter Carnielli (UNICAMP, Brazil). We gladly accepted it and we thank Walter for the idea!
Why "Logica Copernicana": Two revolutions of thought
By Walter Carnielli
The Copernican Revolution marked a profound shift in the human understanding of the cosmos.
In the sixteenth century, Nicolaus Copernicus of Torun (1473–1543), in his De revolutionibus orbium coelestium
(On the Revolutions of the Celestial Spheres, 1543), proposed that the Sun, not the Earth, stands at the center of the planetary system.
By doing so, he displaced humankind from the privileged position imagined by ancient cosmology and opened the way for modern science.
Only Aristarchus of Samos (3rd century BCE) ventured to think of a heliocentric model, suggesting that the Earth orbits the Sun—a daring idea that was soon dismissed and largely forgotten.
When Nicolaus Copernicus revived this vision nearly eighteen centuries later, he transformed what had been a philosophical speculation into a structured astronomical theory,
Copernicus’s heliocentric model explained the apparent motions of the planets more simply and coherently, showing that what seemed to revolve around us was, in fact, the result of our own motion.
Nearly a century later, Galileo Galilei (1564–1642) gave empirical force to Copernicus’s vision.
Through his telescopic observations—collected in Sidereus Nuncius (The Starry Messenger, 1610) and later defended in Dialogo sopra i due massimi sistemi del mondo
(Dialogue Concerning the Two Chief World System, 1632)—Galileo confirmed that the Earth is not the center of celestial motion.
He discovered the moons of Jupiter, the phases of Venus, and the rugged surface of the Moon—observations that supported the Copernican model and challenged Aristotelian cosmology.
Galileo’s work transformed Copernicus’s mathematical hypothesis into an empirical paradigm of the new science.
A similar transformation occurred in the twentieth century with the rise of non-classical logics.
Just as Copernicus questioned the geocentric order of the universe, logicians began to question the absolute dominance of the so-called "classical logic" as the sole framework for rational thought.
Intuitionistic, many-valued, paraconsistent, modal, fuzzy, and other non-classical systems revealed that logical space could be richer and more diverse than previously believed.
Both revolutions share a common spirit: they redefined the center of reasoning. Copernicus decentered the Earth; Galileo demonstrated this empirically; and modern logic decentered the classical ideal of one single logic.
Each opened new horizons for inquiry, showing that knowledge evolves not by preserving certainty, but by expanding the limits of what can be thought.