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Immanuel Kant made important scientific discoveries about the earth and the universe.

Immanuel Kant and His Important Scientific Discoveries

Immanuel Kant is famous for his philosophy of politics, ethics, and metaphysics, but he was also a pioneer in the natural sciences, specifically astronomy.

Despite having no formal training in the sciences, Kant predicted the effect of tides on the earth’s rotation, the composition of nebulae and the solar system, and a multi-galaxy universe in 1755; his theories weren’t fully confirmed until the 1900’s.[1]

Although involved with universities at the time, Kant didn’t have a background in science. He read the works of others (like his contemporary Sir Isaac Newton) and correctly reasoned his astronomical theories. Kant wouldn’t be proven right until Edwin Hubble confirmed Kant’s guesswork starting in the 1920’s.[2]

Kant’s most notable discoveries in astronomy, both from his General History of Nature and Theory of the Heavens (read online) (1755), include:

  • Pointing out that the friction between the tides and the earth’s surface cause the earth’s rotation speed to slow (a diminution of the earth’s rotational speed). A fact that was not confirmed until 1840.[3][4]

Earth Rotation Slowing down. Without Kant insights, we wouldn’t know things like this.

  • Correctly deducing the composition of the galaxies and solar systems (Nebular Hypothesis), expanding astronomy beyond our solar system for the first time. Kant laid out the Nebular hypothesis where he correctly postulated that the Solar System formed from a large cloud of gas, a nebula. He also correctly deduced that the Milky Way was a large disk of stars, which he theorized also formed from a (much larger) spinning cloud of gas. He also correctly suggested that other nebulae might also be similarly large and distant disks of stars. He also somewhat correctly suggested that there must be billions of galaxies (there are likely more). These theories weren’t shown correct until the 1900’s.[5]

Nebular Hypothesis – Formation of the Solar System. Kant was the first to give insight into the Nebular Hypothesis.

TIP: Other works of Kant focused on the natural sciences include Thoughts on the True Estimation of Living Forces (1746–1749), Physical Geography (1802). Read more about Kant’s Philosophy of Science from Stanford Encyclopedia of Philosophy.

Kant After Science

Immanuel Kant is said to have rarely left East Prussia[6], lacked formal training in the natural sciences[7], and spent 10 years locked in his house constructing his highly influential Critique of Pure Reason (1781) (read online) following his contributions to astronomy (and famously after reading David Hume, which made Kant question reason and embrace empiricism, if that gives you an idea of how important Hume is and how seriously Kant took Hume’s ideas).[8]

Kant’s contributions to astronomy were impactful, but his later work, including his synthesizing of the rationalist and empiricist viewpoints and theories on ethics and government, revolutionized philosophy and influenced many famous thinkers from Kant’s time until today.

TIP: See a full list of the works of Kant in order.

PHILOSOPHY: Immanuel Kant – Kant the Philosopher.

FACT: Although involved with the universities since his youth, on March 31, 1770, aged 45, Kant was finally appointed Full Professor of Logic and Metaphysics at the University of Königsberg. It is at this point that his focus fully shifts to philosophy. His “silent decade”, which is a response to David Hume’s philosophical empiricism and gives birth to his major works, start a year later.

Immanuel Kant, other Enlightenment Thinkers, and the Importance of General Knowledge

Immanuel Kant (1724 – 1804) was a German philosopher who is considered the central figure of modern philosophy. His Critique of Pure Reason (1781) was highly influential in American and European politics. That and his other work inspired many of the Enlightenment and post-Enlightenment thinkers.

It was common during the European Enlightenment and Scientific Revolution for great thinkers to dabble in all the sciences and general knowledge. What we call natural science today was called natural philosophy in Kant’s day. Metaphysics (the First Philosophy, or “the book that comes after Physics”), was no more or less important than the natural or social sciences in the 1600 – 1800’s.

Other thinkers from around Kant’s time also dabbled in general knowledge. Newton wrote on economics, as did Hume mentioned above, and Descartes famously mixes metaphysics and physics in his Principles of Philosophy (read online) (buy now), where he correctly deduces most of the laws of motion before Newton.

With the printing press only being invented in the 1500’s, just like Aristotle, Plato, and other Greeks, the great thinkers of yesterday rarely specialized and commonly studied and wrote on all the sciences, social, metaphysical, and natural sciences.

Another common theme is that many of the greats focused on moral philosophies toward the end of their lives. Even Smith, the father of capitalism, considered his moral philosophy his most important work. Likewise, Kant starts his career by focusing on the natural science and then moves toward political and moral philosophy in his later years.

Today, like Smith predicted, people are highly specialized, but with this we lose one of the things that helped create the enlightenment, love and understanding of all the studies, including the most philosophical ones like ethics and metaphysics.

PHILOSOPHY: Immanuel Kant – Kant on living the good life.

FACT: Thomas Hobbes, another philosopher who was influential in political philosophy, didn’t write any major political works until after 61 years of age.


Quotes About Kant

Both quotes below are taken from a Wikipedia article on explaining Kant’s early work.

According to Lord Kelvin:

“Kant pointed out in the middle of last century, what had not previously been discovered by mathematicians or physical astronomers, that the frictional resistance against tidal currents on the earth’s surface must cause a diminution of the earth’s rotational speed. This immense discovery in Natural Philosophy seems to have attracted little attention—indeed to have passed quite unnoticed—among mathematicians, and astronomers, and naturalists, until about 1840 when the doctrine of energy began to be taken to heart.”

— Lord Kelvin, physicist, 1897

According to Thomas Huxley:

“The sort of geological speculation to which I am now referring (geological aetiology, in short) was created as a science by that famous philosopher, Immanuel Kant, when, in 1775 [1755], he wrote his [General Theory of the Heavens] General Natural History and Theory of the Celestial Bodies; or, an Attempt to Account for the Constitutional and Mechanical Origin of the Universe, upon Newtonian Principles.

— Thomas H. Huxley, 1869
Immanuel Kant Part 1 – A long overview on Kant, the only thing I could find that mentioned his natural philosophy (AKA science).


Immanuel Kant is famous for his metaphysical, ethic, and political philosophies, but years before that, in 1755, he made some important discoveries in the natural sciences, that weren’t fully confirmed until the 1900’s.


  1. Immanuel Kant” Philosophers.co.uk
  2. Immanuel Kant: Discoverer of Nebulae and the Multi-galaxy Universe” Futurism.com
  3. Kant’s cosmogony as in his essay on the retardation of the rotation of the …” books.Google.com
  4. Reviewed Work: Kant’s Cosmogony: As in His Essay on the Retardation of the Earth, and in His Natural History and Theory of the Heavens by W. Hastie” JSTOR.org
  5. Immanuel Kant” Wikipedia.org
  6. “A Companion to Kant” books.Google.com
  7. Kant’s Philosophy of Science” plato.Stanford.edu
  8. Immanuel Kant” Carroll.edu

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Bradford on

This dude was an idiot

Thomas DeMichele
Thomas DeMichele on

To quote the equally lame Pliny the Younger, quoting Cicero, and pertaining to the moral ethics of a horse, Dudus erat stultus.