Great Scientists and their Inventions

Aristotle (384 – 322 BC.)


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Aristotle’s influence on western culture and science has been enormous. His writings, many of which survived the great periods of turmoil and the millennia separating us from him, show him to be a man of tremendous intellect who thought deeply about the world.

The volume, extent and depth of his work is humbling.

Aristotle’s Science

Aristotle wanted a piece of all available intellectual action.

He published a large number of works in fields as diverse as poetry and politics; religion and rhetoric; logic and literary theory; music and metaphysics; and many other fields, centered chiefly around philosophy.

He also published a substantial body of scientific work, which we’ll now look at briefly.

Chemistry and Alchemy

The Ancient Elements

Modern chemistry is based on the periodic table’s elements and their compounds.

Aristotle’s ‘chemistry’ was based on the system developed by Empedocles (c. 490 BC – c. 430 BC).

Aristotle’s Perfect First Element

Aristotle, after much thought, added another element. He called this the first element; it later came to be called the aether or the quintessence. This element did not exist on Earth, it only existed in the heavens.

Aristotle believed that the four earthly elements moved in straight lines, but the ‘first element’ followed a perfect path, a circle, explaining why heavenly bodies followed circular paths around Earth. The perfect ‘first element’ did not combine with other elements, it remained forever pure. The sun, moon, planets and stars were perfect because they contained this element.

Aristotle’s Elements






Aristotle’s Influence on Alchemy

The science of alchemy was built around the five Ancient Greek elements.

Alchemists believed that a small amount of Aristotle’s quintessence had drifted down to Earth and that if they could harness its properties they could cure diseases with it. Some came to identify it with the Philosopher’s Stone, which could be used to turn other metals into gold and grant eternal life to people who consumed it.

While modern chemistry owes a debt to the practical methods developed by alchemists, their theories, based on the ideas of Empedocles and Aristotle, hindered the development of chemistry for over 2000 years.


In contrast to his highly theoretical approach to chemistry, Aristotle the biologist was perfectly happy to get his hands dirty dissecting animals. His father and uncle were physicians, which may have influenced Aristotle’s approach. His biological observations were more accurate than his chemical ones.

“By ‘life,’ we mean a thing that can nourish itself and grow and decay.”

Aristotle produced his own classification of life, placing animals in groups according to features the animals had in common. He called each of these groups a genus and identified 11 of these.

Aristotle went out to sea with fishermen. He observed wildlife and examined fishermen’s catches.

He was the first scientist to write that dolphins are not fish – he observed that they have lungs, they give birth to live offspring, which are fed milk by their mothers. He grouped dolphins with porpoises and whales in a genus he called Cetacea.

Aristotle identified close to 600 species of life.

He was the first scientist to place species into different groups based on their shared features, a method later adopted by biologists such as Carolus Linnaeus.

Astronomy and Physics

Aristotle tried to understand the universe by just thinking about it rather than performing experiments or making measurements. This undermined his chances of formulating successful theories.


Aged just 32, Alexander had died in the year 323 BC in Babylon, far from his Macedonian homeland.

Alexander’s Macedonian army had united Ancient Greece, but not without spilling a lot of blood. With the death of Alexander, anti-Macedonian sentiment flourished in Athens. The result of this was that in 322 BC Aristotle, who was Macedonian, fled to the safety of his mother’s estate in Chalcis.


We are what we repeatedly do. Excellence, then, is not an act, but a habit.

It is the mark of an educated mind to be able to entertain a thought without accepting it.

What is a friend? A single soul dwelling in two bodies.

Pleasure in the job puts perfection in the work.

Happiness depends upon ourselves.

For the things we have to learn before we can do them, we learn by doing them.

All men by nature desire knowledge.

I count him braver who overcomes his desires than him who conquers his enemies; for the hardest victory is over self.

In all things of nature there is something of the marvelous.

No great genius has ever existed without some touch of madness.