Philosophy of Nature Aristotle sees the universe as a scale lying between the two extremes: form without matter is on one end, and matter without form is on the other end. The passage of matter into form must be shown in its various stages in the world of nature.
To do this is the object of Aristotle's physics, or philosophy of nature. It is important to keep in mind that the passage from form to matter within nature is a movement towards ends or purposes. Everything in nature has its end and function, and nothing is without its purpose. Everywhere we find evidences of design and rational plan. No doctrine of physics can ignore the fundamental notions of motion, space, and time. Motion is the passage of matter into form, and it is of four kinds: 1 motion which affects the substance of a thing, particularly its beginning and its ending; 2 motion which brings about changes in quality; 3 motion which brings about changes in quantity, by increasing it and decreasing it; and 4 motion which brings about locomotion, or change of place.
Of these the last is the most fundamental and important. Aristotle rejects the definition of space as the void. Empty space is an impossibility. Hence, too, he disagrees with the view of Plato and the Pythagoreans that the elements are composed of geometrical figures. Space is defined as the limit of the surrounding body towards what is surrounded. Time is defined as the measure of motion in regard to what is earlier and later. If there where no change in the universe, there would be no time.
Since it is the measuring or counting of motion, it also depends for its existence on a counting mind. If there were no mind to count, there could be no time. Back to Subtopic page. Click image to enlarge it Editor's comment Here are the views about the Earth and nature that held sway in Western minds for years. There are four causes: 1. And in return, the unmoved mover moved all the other celestial spheres without interfering in the mechanics of each other.
Therefore, Aristotle believed that all the heavenly spheres were somehow related to each other. Though, he never gave an explanation that what was the prime mover or the unmoved mover. According to Aristotelian philosophy, all bodies tend to move towards their natural place.
Therefore, first comes earth, then water, then air, and finally fire. He argued that the natural place of the earth is the center of the universe. Similarly, the natural place of water is a concentric shell around the earth.
In other words, as the earth is the heaviest, therefore, it will eventually sink in water. Likewise, the natural place of air is a concentric shell around water. Simply because you can see the bubbles air rise in water. And at last, the natural place of fire is higher above the air but quite lower than the sphere of the moon.
Because around the sphere of the moon, there is nothing to sustain terrestrial matter around any celestial sphere. No one can argue that there were so many inadequacies in the Aristotelian universe.
I mean take the example of the retrograde motion of Mars. Even at the time of Aristotle himself, this retrograde motion of Mars was clearly observed. Therefore, was directly violating the principles of the Aristotelian universe.
On the contrary, he considered the motion of Mars to be exceptional. On the other hand, Aristotle believed that there is no such thing as a vacuum.
He used to argue that in a vacuum; the speed would become infinite which was considered impossible in the Aristotelian universe. Finally, with the arrival of the scientific revolution, all the controversy related to Aristotelian physics came to rest. I mean the experimental methods of Galileo proved the existence of Vaccum. On the other hand, the combined work of Galileo, Copernicus, and of course work of Tycho Brahe made the Aristotelian universe Obsolete. Later, Kepler fused the work of Brahe with the Copernicus model of the solar system to form his own Kepler law of Planetary motion.
Well, my concluding remark is that theories of the origin of the universe can never be solved with full accuracy. I mean, a theory that dominated almost 18 centuries can finally become obsolete.
Then what could you say for the current big bang model of the universe? Well, who knows maybe the Big Bang theory of the universe will also become obsolete in the near coming future.
What do you think? Is it possible? If you like this article, share it if you like, like it if you share it.
You can also find us on Mix, Twitter, Pinterest, and Facebook. I am a mechanical engineer by profession. Just because of my love for fundamental physics, I switched my career, and therefore I did my postgraduate degree in physics. Right now I am a loner as ever and a Physics blogger too. He used the astronomical records of the Babylonians and Egyptians to accurately predict a solar eclipse in the sixth century BC.
Thales believed the Earth was flat and floated on water like a log. Aristotle, who lived from to BC, believed the Earth was round. He thought Earth was the center of the universe and that the Sun, Moon, planets, and all the fixed stars revolved around it. Aristotle's ideas were widely accepted by the Greeks of his time. The exception, a century later, was Aristarchus, one of the earliest believers in a heliocentric or sun-centered universe. In the s BC, Hipparchus, the most important Greek astronomer of his time, calculated the comparative brightness of as many as 1, different stars.
He also calculated the Moon's distance from the Earth. The first astronomer to make truly scientific maps of the heavens, Claudius Ptolemaeus better known as Ptolemy of Alexandria , came along years later. Like most astronomers before him, he believed the Sun, Moon, and other planets circled the Earth. He thought that each space body moved in a small circle an epicycle that was itself orbiting Earth.
This explained why planets sometimes appeared to travel backward in the sky. The Earth-centered view of the universe was widely accepted for about years. It was not seriously challenged until , when the Polish monk Nicolaus Copernicus suggested that the Sun was at the center of the universe. Because the Church taught that the Earth was central, Copernicus' theory was regarded as heresy.
Perhaps this is why he did not want it published until after his death. Copernicus' published theory, On the Revolution of the Celestial Spheres , met with great hostility from the Church. The two events most responsible for eventual acceptance of Copernicus' views were Tycho Brahe's precise observations of the sky and Galileo's use of the telescope. One night in , Danish astronomer Tycho Brahe saw what he thought was a brilliant new star in the constellation Cassiopeia.
We now know he was observing a supernova. In , a second supernova was observed. These discoveries caused scientists to seriously question Ptolemy's theory that all stars were contained in an outermost sphere of the universe that never changed.
In , Italian scientist Galileo Galilei heard about the invention of a spyglass. He made one for himself and turned it on the heavens. One of his first discoveries was of four moons circling the planet Jupiter. Galileo's telescope revealed a miniature version of Copernicus' solar system , with the moons moving around the planet in simple, circular orbits.
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