Aristotle’s views on the natural world established the basis of scientific thought and civilization. Aristotle’s philosophy is relaying on experience, observation, and logical reasoning.
His approach to natural philosophy consists of studying the cosmos and nature through careful observation and analysis. His three foundational works in this area are “Metaphysics,” “Physics” and “On the Heavens.”
In “Metaphysics,” Aristotle introduced his theory of the four causes. This theory creates a framework for understanding how nature works.
According to the four-cause theory, all entities in the world can be analysed by identifying their material cause (what they are made of), formal cause (their structure or shape), efficient cause (what brings them into existence) and final cause (their purpose of goal).
By applying observation and the four-cause theory, Aristotle established a classification of objects and animals. In his work titled “History of Animals,” he categorized animals according to their mode of reproduction and whether they possess blood.
Aristotle’s most innovative analysis tool is the final cause or the study of purpose (in Greek “telos”). Thus, the science that studies purpose is called “teleology.”
According to Aristotle, everything in nature has a purpose or final cause. He considered the world governed by a natural force that drives each entity towards its purpose.
At the same time, Aristotle rejected the idea of emptiness or void in the universe. He believed that nature abhors vacuum in the sense that it will immediately fill any empty space. Even a barren field will be soon covered by weeds or other plants.
Aristotle regarded empirical, systematic observation as the best method for drawing accurate conclusions. In this way, he established the empirical approach underlying science.
Nonetheless, it is not surprising that Aristotle’s observations frequently proved incorrect. Bear in mind that he lacked proper measurement tools and that the knowledge cumulated by prior scientists was modest and unreliable.
Due to its sound logic, Aristotle’s natural philosophy went to exert a large influence on scholars during the Middle Ages and the Renaissance.
Aristotle’s views on astronomy
In his work titled “On the Heavens,” Aristotle presented his views on astronomy. His cosmology was geocentric, that is, it regarded the Earth at the centre of the universe.
Aristotle knew the Earth to be spherical, but regarded it as stationary in the middle of the cosmos. This means that the sun, moon, planets, and stars are all moving in circular orbits around the Earth.
How do celestial bodies hang in the universe? Aristotle did not know, but theorized that the cosmos is made of concentric spheres, each carrying a celestial body.
He imagined the spheres to be perfectly round and made of a fifth element called aether or quintessence. Their movement, he theorized, is uniform and circular, orbiting around the Earth.
For what concerns the stars, Aristotle described them as eternal and unchanging. He imagined them made of a different substance than the Earth, but did not go into details.
How did Aristotle categorize celestial bodies? He grouped them according to their movement. While he regarded the stars as fixed and eternal, the planets and the moon move around the Earth.
Despite its inaccuracy, Aristotle’s model of the cosmos was accepted for centuries. The Egyptian astronomer Ptolemy (90-168 AD) still relied on Aristotle’s geocentric views. Eventually, those were replaced by the heliocentric theory first elaborated by Copernicus (1473-1543).
Aristotle’s views on animal and human biology
Aristotle presented his view on biology in two works titled “History of Animals” and “Parts of Animals.” His biological studies are the result of systematically observing and grouping living organisms in categories. He examined and catalogued species depending on their anatomical features, behaviour, and habitat.
In his main classification, Aristotle referred to the presence or absence of blood. This criterion led him to grouping animals into blooded (vertebrates) and bloodless (invertebrates).
Aristotle described the distinct behaviour of animal species and attributed it to their innate characteristics and habits. He also describes various modes of reproduction among different species, and the roles of male and female.
How did Aristotle explain the existence of life? To explain it, he created the concept “vitalism.” The idea behind vitalism is that living organisms possess a life force that distinguishes them from inert matter.
As a second explanation for the existence of life, Aristotle used “spontaneous generation.” This theory sustains that inert matter can, under certain conditions, generate living organisms or become living organisms.
Aristotle’s views on human anatomy appear in his works “Parts of Animals” and “On the Parts of Animals.” He arrived at those views by dissecting animals and comparing the results with human physiology.
His overall method didn’t change. Aristotle applied his four-cause theory also to studying humans. He observed that, just like it happens for animals, humans are made of matter (“hyle” in Greek) and form (“morphe”). This doctrine is known as the “hylomorphic theory.”
By applying the hylomorphic theory, he identified the parts or organs (e.g., the heart, the brain, the eyes, etc.) in the human body and described their specific functions.
Aristotle described the role of human males and females in reproduction, but for the embryo, the came up with the theory of “epigenesis.” According to this theory, the embryo does not pre-exist in its complete form and develops only gradually.
Aristotle’s views on plants
For what concerns plants, Aristotle wrote his observations in his works “History of Plants” and “On the Soul.” He rated plants as living entities that grow, feed, digest and reproduce. For categorizing them, he used characteristics such as structure and size, as well as mode of reproduction.
In his book about the soul, Aristotle theorized that plants possess “a nutritive soul,” one of the three types of souls he identified. The nutritive soul governs the functions of nutrition, growth, and reproduction (for instance, through seeds).
“History of Plants” describes the processes of growth and reproduction in plants, describing the functions of seeds, roots, stems, leaves, and flowers. However, Aristotle’s classification of plants is unsophisticated. It simply groups them into trees, shrubs, and herbs.
Aristotle’s views on meteorology
Aristotle’s observations on the weather appear in his work “Meteorology.” Instead of attributing the weather changes to supernatural causes, he tried to find logical explanations. He believed that weather events result from natural processes, not from divine intervention.
He theorized that four elements (earth, water, air, and fire) shape the weather. The predominance of specific elements (for instance, heat, moisture, wind) is what produces a specific type of weather.
In his work “Meteorology,” Aristotle also provides insights on the sea and tides. From observing the movements of the sea, he arrived at the conclusion that tides are caused by the moon. Its movements lead to high and low tides. He also noted that winds can change the sea’s appearance and behaviour.
Aristotle’s views on natural philosophy show how much it’s possible if you observe the facts and think logically. If you use a logical, systematic approach in your own life, you should do much better than average.
If you are interested in applying Aristotelian principles to everyday life, I recommend you my book “The 10 principles of rational living.”
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