84-406: Spontaneous generation is a superseded scientific theory that held that living creatures could arise from nonliving matter and that such processes were commonplace and regular. It was hypothesized that certain forms, such as fleas , could arise from inanimate matter such as dust, or that maggots could arise from dead flesh. The doctrine of spontaneous generation was coherently synthesized by
168-554: A scientific consensus , but replaced after more empirical information became available that identified flaws and prompted new theories which better explain the available data. Pre-modern explanations originated before the scientific method , with varying degrees of empirical support. Some scientific theories are discarded in their entirety, such as the replacement of the phlogiston theory by energy and thermodynamics . Some theories known to be incomplete or in some ways incorrect are still used. For example, Newtonian classical mechanics
252-417: A connection between the soul and the physical world, as they suggest that they are made of the same material, air. From this, Anaximenes suggested that everything, whether it be an individual soul or the entire world, operates under the same principles in which things are held together and guided by the air. In Ancient Greek , the words for wind and for soul shared a common origin. Anaximenes's philosophy
336-482: A divine explanation, they are regarded as the first philosophers in the Western world. According to Diogenes Laertius , Anaximenes lived approximately from 585 to 524 BC. Anaximenes is only known to have written one full text, which may have been a response to Anaximander's text On Nature . It was described by Theophrastus as having a "simple and economical Ionic style". Anaximenes died c. 526/525 BC . What
420-456: A kind of foam itself (composed, as it was, from a mixture of water and pneuma ). For Aristotle, the generative materials of male and female animals (semen and menstrual fluid) were essentially refinements, made by male and female bodies according to their respective proportions of heat, of ingested food, which was, in turn, a byproduct of the elements earth and water. Thus any creature, whether generated sexually from parents or spontaneously through
504-414: A meat broth in a swan neck flask ; the bend in the neck of the flask prevented falling particles from reaching the broth, while still allowing the free flow of air. The flask remained free of growth for an extended period. When the flask was turned so that particles could fall down the bends, the broth quickly became clouded. However, minority objections were persistent and not always unreasonable, given that
588-494: A model in which the qualitative traits of a substance are determined by quantitative factors. Anaximenes believed that the universe was initially made entirely of air and that liquids and solids were then produced from it through condensation. He also used air to explain the nature of the Earth and the surrounding celestial bodies. He believed in a flat Earth that emerged as one of the first things to be condensed from air. This Earth
672-460: A parent, is needed. Supposed examples included the seasonal generation of mice and other animals from the mud of the Nile , the emergence of fleas from inanimate matter such as dust, or the appearance of maggots in dead flesh. Such ideas have something in common with the modern hypothesis of the origin of life , which asserts that life emerged some four billion years ago from non-living materials, over
756-462: A range of creatures from different sorts of inanimate matter. The testaceans (a genus which for Aristotle included bivalves and snails), for instance, were characterized by spontaneous generation from mud, but differed based upon the precise material they grew in—for example, clams and scallops in sand, oysters in slime, and the barnacle and the limpet in the hollows of rocks. Athenaeus dissented towards spontaneous generation, claiming that
840-455: A recipe for mice (a piece of dirty cloth plus wheat for 21 days) and scorpions ( basil , placed between two bricks and left in sunlight). His notes suggest he may have attempted to do these things. Where Aristotle held that the embryo was formed by a coagulation in the uterus , the English physician William Harvey showed by way of dissection of deer that there was no visible embryo during
924-460: A reflection of sunlight off of clouds, and he theorized that the various colors were caused by an interaction of light and darkness. Anaximenes's views have been interpreted as reconciling those of his two predecessors, Thales and Anaximander. Air as the arche is a limitless concept, which resembled Anaximander's theory that the arche was the abstract infinite that he called apeiron (Ancient Greek: ἄπειρον , lit. 'unlimited, 'boundless'). At
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#17328842186931008-462: A single form approximately four billion years ago, attention has instead turned to the origin of life . "Spontaneous generation" means both the supposed processes by which different types of life might repeatedly emerge from specific sources other than seeds, eggs, or parents, and the theoretical principles presented in support of any such phenomena. Crucial to this doctrine are the ideas that life comes from non-life and that no causal agent, such as
1092-575: A single substance. This description came to be widely accepted in philosophy. Practitioners of Aristotelian philosophy further considered Anaximenes to be a founder of naturalism . After Aristotle, Theophrastus continued the doxography of the Milesian philosophers and other Ionians. He described Anaximenes as a natural philosopher . Other ancient philosophers who analyzed the work of Anaximenes include Simplicius , Aetius , Hippolytus, and Plutarch . Georg Wilhelm Friedrich Hegel said that Anaximenes
1176-598: A time span of millions of years, and subsequently diversified into all the forms that now exist. The term equivocal generation , sometimes known as heterogenesis or xenogenesis , describes the supposed process by which one form of life arises from a different, unrelated form, such as tapeworms from the bodies of their hosts. Active in the 6th and 5th centuries BCE, early Greek philosophers, called physiologoi in antiquity (Greek: φυσιολόγοι; in English, physical or natural philosophers ), attempted to give natural explanations of phenomena that had previously been ascribed to
1260-494: A variety of anchovy did not generate from roe , as Aristotle stated, but rather, from sea foam . As the dominant view of philosophers and thinkers continued to be in favour of spontaneous generation, some Christian theologians accepted the view. The Berber theologian and philosopher Augustine of Hippo discussed spontaneous generation in The City of God and The Literal Meaning of Genesis , citing Biblical passages such as "Let
1344-558: A variety of routes, including touching a contaminated object , blood , and contaminated water . Malaria was discovered to be a mosquito-borne disease , explaining why avoiding the "bad air" near swamps prevented it. Increasing ventilation of fresh air, one of the remedies proposed by miasma theory, does remain useful in some circumstances to expel germs spread by airborne transmission , such as SARS-CoV-2 . Some theories originate in, or are perpetuated by, pseudoscience , which claims to be both scientific and factual, but fails to follow
1428-580: Is accurate enough for practical calculations at everyday distances and velocities, and it is still taught in schools. The more complicated relativistic mechanics must be used for long distances and velocities nearing the speed of light , and quantum mechanics for very small distances and objects. Some aspects of discarded theories are reused in modern explanations. For example, miasma theory proposed that all diseases were transmitted by "bad air". The modern germ theory of disease has found that diseases are caused by microorganisms, which can be transmitted by
1512-556: Is generally accepted that Anaximenes was instructed by Anaximander, and many of their philosophical ideas are similar. While Anaximenes was the preeminent Milesian philosopher in Ancient Greece, he is often given lower importance than the others in the modern day. Anaximenes held that air could change into other forms through either rarefaction or condensation . Condensation would make the air denser, turning it into wind, clouds, water, earth, and finally stone. Rarefaction would make
1596-473: Is known about Anaximenes's philosophy is what was preserved by later philosophers, particularly Aristotle and Theophrastus . According to their writings, each philosopher of the Milesian School was a material monist who sought to discover the arche (Ancient Greek: wikt:ἀρχή , lit. 'beginning, origin'), or the one, underlying basis of all things. This is generally understood in
1680-444: Is known of Anaximenes's life and work, as all of his original texts are lost. Historians and philosophers have reconstructed information about Anaximenes by interpreting texts about him by later writers. All three Milesian philosophers were monists who believed in a single foundational source of everything: Anaximenes believed it to be air, while Thales and Anaximander believed it to be water and an undefined infinity , respectively. It
1764-416: Is supported by the pressure of air underneath it to keep it afloat. Anaximenes considered celestial objects to be those which had separated from the Earth. The philosophers who recorded Anaximenes's ideas disagree as to how he theorized this happened. He may have described them as evaporating or rarifying into fire. He is said to have compared the movement of the Earth, Sun, and stars to leaves floating in
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#17328842186931848-414: Is water in earth, and air in water, and in all air is vital heat so that in a sense all things are full of soul. Therefore living things form quickly whenever this air and vital heat are enclosed in anything. When they are so enclosed, the corporeal liquids being heated, there arises as it were a frothy bubble. With varying degrees of observational confidence, Aristotle theorized the spontaneous generation of
1932-460: The History of Animals , many creatures form not through sexual processes but by spontaneous generation: Now there is one property that animals are found to have in common with plants. For some plants are generated from the seed of plants, whilst other plants are self-generated through the formation of some elemental principle similar to a seed; and of these latter plants some derive their nutriment from
2016-514: The Phaedo , rejecting it with the argument that one's physical state does not determine their fate. In the Timaeus , Plato favorably mentions Anaximenes's theory of matter and its seven states from stone to fire. Aristotle was critical of the ideas of Anaximenes. In his Metaphysics , Aristotle characterized Anaximenes and his predecessors as monists , those who believe that all things are composed of
2100-467: The apeiron, eternally in motion, served as a platform on which elemental opposites (e.g., wet and dry , hot and cold ) generated and shaped the many and varied things in the world. According to Hippolytus of Rome in the third century CE, Anaximander claimed that fish or fish-like creatures were first formed in the "wet" when acted on by the heat of the sun and that these aquatic creatures gave rise to human beings. The Roman author Censorinus , writing in
2184-431: The barnacle goose myth was evidence for the virgin birth of Jesus . Where the practice of fasting during Lent allowed fish, but prohibited fowl, the idea that the goose was in fact a fish suggested that its consumption be permitted during Lent. The practice was eventually prohibited by decree of Pope Innocent III in 1215. After Aristotle’s works were reintroduced to Western Europe, they were translated into Latin from
2268-401: The male's seed imposed form, the set of characteristics passed down to offspring on the "matter" ( menstrual blood ) supplied by the female. Thus female matter is the material cause of generation—it supplies the matter that will constitute the offspring—while the male semen is the efficient cause , the factor that instigates and delineates the thing's existence. Yet, Aristotle proposed in
2352-399: The scientific method . Scientific theories are testable and make falsifiable predictions . Thus, it can be a mark of good science if a discipline has a growing list of superseded theories, and conversely, a lack of superseded theories can indicate problems in following the use of the scientific method. Fringe science includes theories that are not currently supported by a consensus in
2436-424: The theo , or divine world. Anaximenes considered air to be divine in a sense, but he did not associate it with deities or personification. He presented air as the first cause that propelled living systems, giving no indication that air itself was caused by anything. Anaximenes also likened the soul to air, describing it as something that is driven by breath and wills humans to act as they do. These beliefs draw
2520-463: The water cycle : the processes of rarefaction and condensation . He proposed that each substance is created by condensation to increase the density of air or by rarefaction to decrease it. The rarefaction process described by Anaximenes is often compared to felting . Temperature was of particular importance to Anaximenes's philosophy, and he developed an early concept of the connection between temperature and density. He believed that expanded air
2604-411: The 3rd century, reported: Anaximander of Miletus considered that from warmed up water and earth emerged either fish or entirely fishlike animals. Inside these animals, men took form and embryos were held prisoners until puberty; only then, after these animals burst open, could men and women come out, now able to feed themselves. The Greek philosopher Anaximenes , a pupil of Anaximander, thought that air
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2688-458: The English biologist Thomas Henry Huxley proposed the term abiogenesis for this same process, and adopted biogenesis for the process by which life arises from existing life. Superseded scientific theories This list includes well-known general theories in science and pre-scientific natural philosophy and natural history that have since been superseded by other scientific theories . Many discarded explanations were once supported by
2772-500: The Greek philosopher and naturalist Aristotle , who compiled and expanded the work of earlier natural philosophers and the various ancient explanations for the appearance of organisms . Spontaneous generation was taken as scientific fact for two millennia. Though challenged in the 17th and 18th centuries by the experiments of the Italian biologists Francesco Redi and Lazzaro Spallanzani , it
2856-484: The Needham experiment in 1768, where he attempted to exclude the possibility of introducing a contaminating factor between boiling and sealing. His technique involved boiling the broth in a sealed container with the air partially evacuated to prevent explosions. Although he did not see growth, the exclusion of air left the question of whether air was an essential factor in spontaneous generation. But attitudes were changing; by
2940-576: The Pre-Socratic philosophers that succeeded him, such as Heraclitus , Anaxagoras , Diogenes of Apollonia , and Xenophanes . He also provided early examples of concepts such as natural science , physical change , and scientific writing . Anaximenes was born c. 586/585 BC . Surviving information about the life of Anaximenes is limited, and it comes primarily from what was preserved by Ancient Greek philosophers, particularly Aristotle and Theophrastus . According to Theophrastus, Anaximenes
3024-500: The agency of the gods. The physiologoi sought the material principle or arche (Greek: ἀρχή) of things, emphasizing the rational unity of the external world and rejecting theological or mythological explanations. Anaximander , who believed that all things arose from the elemental nature of the universe, the apeiron (ἄπειρον) or the "unbounded" or "infinite", was likely the first western thinker to propose that life developed spontaneously from nonliving matter. The primal chaos of
3108-490: The air less dense as it eventually becomes fire. Anaximenes also developed a model of the Earth, describing it as a flat disc floating atop the air while the Sun and stars are also flat and float alongside it. He described the Sun as revolving around the Earth, causing it to be obscured by higher lands during the night. As one of the Milesian philosophers, Anaximenes was one of the earliest figures to develop science. He influenced many of
3192-547: The beginning, and those of animals in the aether . Another philosopher, Xenophanes , traced the origin of man back to the transitional period between the fluid stage of the Earth and the formation of land, under the influence of the Sun. In what has occasionally been seen as a prefiguration of a concept of natural selection , Empedocles accepted the spontaneous generation of life, but held that different forms, made up of differing combinations of parts, spontaneously arose as though by trial and error: successful combinations formed
3276-445: The causes of other natural phenomena. Like Anaximander, he believed that thunder and lightning occurred when wind emerged after being trapped in a cloud. Earthquakes, he asserted, were the result of alternating drying and wetting of the earth, causing it to undergo a cycle of splitting and swelling. He was the first philosopher to attempt a scientific explanation of rainbows, and the only one to do so until Aristotle. He described them as
3360-419: The commonplace idea that the Sun went underneath the Earth, instead saying that it rotated around the Earth. Hippolytus likened it to a hat spinning around a person's head. It's unknown whether this analogy was of Hippolytus's own creation or if it was part of Anaximenes's explanation. This model of the sun's movement has been interpreted in various ways by subsequent philosophers. Anaximenes also described
3444-564: The context of a substance, though scholars have argued that this may be anachronistic by imposing the Aristotelian notion of substance theory on earlier philosophy. Anaximenes argued that the arche is air. He described several basic elements that he considered to be manifestations of air, sorting them from least dense to most dense: fire, air, wind, clouds, water, earth, and stones. Philosophers have concluded that Anaximenes seems to have based his conclusions on naturally observable phenomena in
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3528-416: The development of natural science . He was the first philosopher to analogize his philosophy in practical terms, comparing the functions of the world to behaviors that can be observed in common activities. In this manner, he was also the first to liken the function of the individual to that of the world. In this case, likening the breath that defines humans to the air that defines the world. His belief that
3612-436: The element of the stars. This is why fire does not generate any animal ... but the heat of the sun and the heat of animals does, not only the heat that fills the seed, but also any other residue of [the animal's] nature that may exist similarly possesses this vital principle. Aristotle drew an analogy between the "foamy matter" (τὸ ἀφρῶδες, to aphrodes ) found in nature and the "seed" of an animal, which he viewed as being
3696-670: The experimental difficulties were far more challenging than the popular accounts suggest. The investigations of the Irish physician John Tyndall , a correspondent of Pasteur and an admirer of his work, were decisive in disproving spontaneous generation. All the same, Tyndall encountered difficulties in dealing with microbial spores , which were not well understood in his day. Like Pasteur, he boiled his cultures to sterilize them, and some types of bacterial spores can survive boiling. The autoclave , which eventually came into universal application in medical practice and microbiology to sterilise equipment,
3780-512: The first month. Although his work predated the microscope , this led him to suggest that life came from invisible eggs. In the frontispiece of his 1651 book Exercitationes de Generatione Animalium ( Essays on the Generation of Animals ), he denied spontaneous generation with the motto omnia ex ovo ("everything from eggs"). The ancient beliefs were subjected to testing. In 1668, the Italian physician and parasitologist Francesco Redi challenged
3864-405: The ground, whilst others grow inside other plants ... So with animals, some spring from parent animals according to their kind, whilst others grow spontaneously and not from kindred stock; and of these instances of spontaneous generation some come from putrefying earth or vegetable matter, as is the case with a number of insects, while others are spontaneously generated in the inside of animals out of
3948-440: The idea of spontaneous generation had been in decline for nearly a century, its supporters did not abandon it all at once. As James Rennie wrote in 1838, despite Redi's experiments, "distinguished naturalists, such as Blumenbach , Cuvier , Bory de St. Vincent , R. Brown , &c." continued to support the theory. Louis Pasteur 's 1859 experiment is widely seen as having settled the question of spontaneous generation. He boiled
4032-399: The idea that maggots arose spontaneously from rotting meat. In the first major experiment to challenge spontaneous generation, he placed meat in a variety of sealed, open, and partially covered containers. Realizing that the sealed containers were deprived of air, he used "fine Naples veil", and observed no worms on the meat, but they appeared on the cloth. Redi used his experiments to support
4116-493: The ideas of Anaximander, only changing it so that it reflected his variety of monism. Anaximenes's philosophy was founded upon that of Anaximander, but tradition holds that he was also critical of his instructor in some areas. Anaximenes also maintained that there must be an empirical explanation for why substances change from one form to another. Anaximenes and Anaximander were similar in that they are not known to have justified why or how changes in physical things take place
4200-487: The individuals present in the observer's lifetime, whereas unsuccessful forms failed to reproduce. In his biological works , the natural philosopher Aristotle theorized extensively the reproduction of various animals, whether by sexual , parthenogenetic , or spontaneous generation. In accordance with his fundamental theory of hylomorphism , which held that every physical entity was a compound of matter and form, Aristotle's basic theory of sexual reproduction contended that
4284-457: The interaction of vital heat and elemental matter, was dependent on the proportions of pneuma and the various elements which Aristotle believed comprised all things. While Aristotle recognized that many living things emerged from putrefying matter, he pointed out that the putrefaction was not the source of life, but the byproduct of the action of the "sweet" element of water. Animals and plants come into being in earth and in liquid because there
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#17328842186934368-501: The mainstream scientific community , either because they never had sufficient empirical support, because they were previously mainstream but later disproven, or because they are preliminary theories also known as protoscience which go on to become mainstream after empirical confirmation. Some theories, such as Lysenkoism , race science or female hysteria have been generated for political rather than empirical reasons and promoted by force. These theories that are no longer considered
4452-482: The microscope to examine foam left over from the process of brewing beer. Where the Dutch microscopist Antonie van Leeuwenhoek described "small spheroid globules", they observed yeast cells undergo cell division . Fermentation would not occur when sterile air or pure oxygen was introduced if yeast were not present. This suggested that airborne microorganisms , not spontaneous generation, was responsible. However, although
4536-521: The most complete representation of reality but remain useful in particular domains or under certain conditions. For some theories, a more complete model is known, but for practical use, the coarser approximation provides good results with much less calculation. Anaximenes of Miletus Anaximenes of Miletus ( / ˌ æ n æ k ˈ s ɪ m ə ˌ n iː z / ; Ancient Greek : Ἀναξιμένης ὁ Μιλήσιος , romanized : Anaximenēs ho Milēsios ; c. 586/585 – c. 526/525 BC )
4620-447: The operation of your sun; so is your crocodile. Antony: They are so. Shakespeare: Antony and Cleopatra : Act 2, scene 7 The author of The Compleat Angler , Izaak Walton repeats the question of the origin of eels "as rats and mice, and many other living creatures, are bred in Egypt, by the sun's heat when it shines upon the overflowing of the river...". While the ancient question of
4704-521: The origin of eels remained unanswered and the additional idea that eels reproduced from corruption of age was mentioned, the spontaneous generation of rats and mice stirred up no debate. The Dutch biologist and microscopist Jan Swammerdam rejected the concept that one animal could arise from another or from putrification by chance because it was impious ; he found the concept of spontaneous generation irreligious, and he associated it with atheism . The Brussels physician Jan Baptist van Helmont described
4788-527: The original Greek or Arabic. They reached their greatest level of acceptance during the 13th century. With the availability of Latin translations, the German philosopher Albertus Magnus and his student Thomas Aquinas raised Aristotelianism to its greatest prominence. Albert wrote a paraphrase of Aristotle, De causis et processu universitatis , in which he removed some commentaries by Arabic scholars and incorporated others. The influential writings of Aquinas, on both
4872-474: The original texts as they were recorded by subsequent authors. Further details of Anaximenes's life and philosophical views are obscure, as none of his work has been preserved, and he is only known through fragments and interpretations of him made by later writers and polemicists. The Anaximenes crater on the Moon is named in his honor. Early medical practice developed ideas similar to Anaximenes, proposing that air
4956-424: The other Milesian philosophers, Thales and Anaximander. These three philosophers together began what eventually became science in the Western world. In ancient Greece, the ideas of Anaximenes were well regarded in philosophy, popularized by various philosophers such as Diogenes of Apollonia , and had a greater presence than the ideas of his predecessors. The other Milesian philosophers have since overshadowed him in
5040-466: The philosophy of Stoicism . The ideas ridiculed in the Aristophanes play The Clouds originated from the ideas of Anaximander and Anaximenes. Philosophers such as Xenophanes later adopted Anaximenes's model of cosmology. Xenophanes's theory that the arche is earth and water has also been interpreted as a response to Anaximenes. Plato referenced the concept of air as the cause of thought in
5124-464: The physical and metaphysical, are predominantly Aristotelian, but show numerous other influences. Spontaneous generation is described in literature as if it were a fact well into the Renaissance . Shakespeare wrote of snakes and crocodiles forming from the mud of the Nile : Lepidus : You’ve strange serpents there? Antony : Ay, Lepidus. Lepidus: Your serpent of Egypt is bred now of your mud by
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#17328842186935208-618: The preexistence theory put forth by the Catholic Church at that time, which maintained that living things originated from parents. In scientific circles Redi's work very soon had great influence, as evidenced in a letter from the English natural theologian John Ray in 1671 to members of the Royal Society of London, in which he calls the spontaneous generation of insects "unlikely". Pier Antonio Micheli , c. 1729 , observed that when fungal spores were placed on slices of melon,
5292-488: The same properties governed the world at a human scale and a universal scale was eventually proven by Isaac Newton . Some of Anaximenes's writings are referenced during the Hellenistic period , but no record of those documents currently exists. Philosophers such as Heraclitus , Anaxagoras , and Diogenes of Apollonia were all directly influenced by the work of Anaximenes. Diogenes of Apollonia adapted Anaximenes's ideas to
5376-427: The same time, air as the arche was a defined substance, which resembled the theory of Thales that the arche was water. Anaximenes adopted a similar design of a flat Earth as Thales. Both proposed that the Earth was flat and that it rested on the substance they believed made up all things; Thales described a disc on water, while Anaximenes described a disc on air. His cosmology also did not diverge significantly from
5460-527: The same type of fungi were produced that the spores came from, and from this observation he noted that fungi did not arise from spontaneous generation. In 1745, John Needham performed a series of experiments on boiled broths . Believing that boiling would kill all living things, he showed that when sealed right after boiling, the broths would cloud, allowing the belief in spontaneous generation to persist. His studies were rigorously scrutinized by his peers, and many of them agreed. Lazzaro Spallanzani modified
5544-474: The secretions of their several organs. According to this theory, living things may come forth from nonliving things in a manner roughly analogous to the "enformation of the female matter by the agency of the male seed" seen in sexual reproduction. Nonliving materials, like the seminal fluid present in sexual generation, contain pneuma (πνεῦμα, "breath"), or " vital heat ". According to Aristotle, pneuma had more "heat" than regular air did, and this heat endowed
5628-514: The start of the 19th century, a scientist such as Joseph Priestley could write that "There is nothing in modern philosophy that appears to me so extraordinary, as the revival of what has long been considered as the exploded doctrine of equivocal, or, as Dr. [Erasmus] Darwin calls it, spontaneous generation." In 1837, Charles Cagniard de la Tour , a physicist, and Theodor Schwann , one of the founders of cell theory, published their independent discovery of yeast in alcoholic fermentation . They used
5712-443: The study of philosophy. Anaximenes was the first philosopher to give an explanation for substances changing from one state to another through a physical process . He may also have been the first philosopher to write in descriptive prose rather than verse, developing a prototype of scientific writing . Only fragments of Anaximenes's writings have been preserved directly, and it is unknown how much these fragments have diverged from
5796-403: The substance with certain vital properties: The power of every soul seems to have shared in a different and more divine body than the so called [four] elements ... For every [animal], what makes the seed generative inheres in the seed and is called its "heat". But this is not fire or some such power, but instead the pneuma that is enclosed in the seed and in foamy matter, this being analogous to
5880-639: The waters bring forth abundantly the moving creature that hath life" ( Genesis 1:20 ) as decrees that would enable ongoing creation. From the fall of the Roman Empire in 5th century to the East–West Schism in 1054, the influence of Greek science declined, although spontaneous generation generally went unchallenged. New descriptions were made. Of the beliefs, some had doctrinal implications. In 1188, Gerald of Wales , after having traveled in Ireland, argued that
5964-413: The way that they do. Anaximander instead invoked metaphors of justice and retribution to describe change, and he made direct appeals to deities and the divine in support of his beliefs. Anaximenes deviated from Anaximander in both of these ideas. Anaximenes was the last of the Milesian philosophers, as Miletus was destroyed by attacking Persian forces in 494 BC. Little of his life is known relative to
6048-553: The wind, though he is also described as likening the stars to nails embedded in the sky. Some scholars have suggested that Anaximenes may have believed both models by distinguishing between planets and stars, which would make him the first person to do so. While the Sun is described as being a flame, Anaximenes thought it was not composed of rarefied air like the stars, but rather of Earth. According to Pseudo-Plutarch , Anaximenes thought that its burning comes not from its composition, but rather from its rapid motion. Anaximenes rejected
6132-465: Was a Milesian philosopher who proposed that apeiron , an undefined and boundless infinity, is the origin of all things. Anaximenes and Anaximander were two of the three Milesian philosophers, along with Thales . These were all philosophers from Miletus who were the first of the Ionian School . As the earliest known figures to have developed theories regarding the material origin of the world without
6216-541: Was an Ancient Greek , Pre-Socratic philosopher from Miletus in Anatolia (modern-day Turkey ). He was the last of the three philosophers of the Milesian School , after Thales and Anaximander . These three are regarded by historians as the first philosophers of the Western world. Anaximenes is known for his belief that air is the arche , or the basic element of the universe from which all things are created. Little
6300-449: Was applied to the generation of living things from once-living organic matter (such as boiled broths), and the English physiologist Henry Charlton Bastian proposed the term archebiosis for life originating from non-living materials. Disliking the randomness and unpredictability implied by the term spontaneous generation , in 1870 Bastian coined the term biogenesis for the formation of life from nonliving matter. Soon thereafter, however,
6384-482: Was centered on a theory of change through ongoing cycles, defined by the movement of air. These cycles consisted of opposite forces interacting with and superseding one another. This is most prominently indicated in the weather and the seasons, which alternate between hot and cold, dry and wet, or light and dark. Anaximenes did not believe that any substance could be created or destroyed, only that it could be changed from one form to another. From this belief, he proposed
6468-413: Was generated only from other life. Pasteur's claim followed the German physician Rudolf Virchow 's doctrine Omnis cellula e cellula ("all cells from cells"), itself derived from the work of Robert Remak . After Pasteur's 1859 experiment, the term "spontaneous generation" fell out of favor. Experimentalists used a variety of terms for the study of the origin of life from nonliving materials. Heterogenesis
6552-468: Was introduced after these experiments. In 1862, the French Academy of Sciences paid special attention to the issue, establishing a prize "to him who by well-conducted experiments throws new light on the question of the so-called spontaneous generation" and appointed a commission to judge the winner. Pasteur and others used the term biogenesis as the opposite of spontaneous generation, to mean that life
6636-449: Was not discredited until the work of the French chemist Louis Pasteur and the Irish physicist John Tyndall in the mid-19th century. Among biologists, rejecting spontaneous genesis is no longer controversial. Experiments conducted by Pasteur and others were thought to have refuted the conventional notion of spontaneous generation by the mid-1800s. Since all life appears to have evolved from
6720-522: Was the basis of health in that it both provides life and carries disease. Anaximenes's conception of air has been likened to the atoms and subatomic particles that make up all substances through their quantitative organization. It has also been compared to the breath of life produced by God in the Old Testament . His understanding of physical properties as quantitative differences that applied at individual and universal scales became foundational ideas in
6804-407: Was the element that imparted life and endowed creatures with motion and thought. He proposed that plants and animals, including human beings, arose from a primordial terrestrial slime, a mixture of earth and water, combined with the sun's heat. The philosopher Anaxagoras , too, believed that life emerged from a terrestrial slime. However, Anaximenes held that the seeds of plants existed in the air from
6888-425: Was the first philosopher to transfer the ideas of natural philosophy into the philosophy of consciousness. Werner Heisenberg said that the philosophy of Anaximenes caused a setback in scientific understanding, as it moved analysis away from physical properties themselves. Karl Popper suggested that Anaximenes and Anaximander developed a philosophy of rationalist critique, allowing criticism of one's teacher, that
6972-568: Was the son of Eurystratus, an associate of the philosopher Anaximander , and lived in Miletus . Anaximenes is recorded as becoming a student of Anaximander. Anaximenes was likely also taught Homeric epics , Greek mythology , and Orphism , which may have influenced his philosophy through their portrayal of the classical elements . It is considered likely that he and the other Milesian philosophers were wealthy, allowing them to dedicate time to philosophy. Anaximenes's apparent instructor, Anaximander,
7056-440: Was thinner and therefore hotter while compressed air was thicker and therefore colder—although modern science has found the opposite to be true. He derived this belief from the fact that one's breath is warm when the mouth is wide while it is cold when the air is compressed through the lips. Anaximenes further applied his concept of air as the arche to other questions. He believed in the physis , or natural world, rather than
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