Aristotle's years of life and contributions to biology. The Birth of Biology
The main contribution to science of the ancient philosopher and scientist is presented in this article.
Aristotle: contribution to science
What is Aristotle's contribution to philosophy?
Before talking about Aristotle's contribution to the development of philosophy, the following should be noted. At the beginning of his journey, he was impressed by the teachings of Plato. But having gradually freed himself from his influence, Aristotle even criticized Plato’s teachings and created his own teaching in philosophy. His philosophy penetrated into all areas of science. The main philosophical works are “Categories”, “Physics”, “Analytics First and Second”, “On the Soul”, “On Celestial Phenomena”, “Politics”, “History of Animals”, “Metaphysics” and “On the Art of Poetry”.
Aristotle combines into being the relationship of the real, the logical and the individual. Aristotle was the first to develop the doctrine that philosophy should study being, abstracting from some of its properties. The difference between philosophy and other sciences is that it explores the very essence of being itself. The essence of existence is based on: matter, form and concept, as well as that which consists of form and matter.
Aristotle's contributions to biology
One of Aristotle's important contributions concerns the field of biology. Based on observations of the structure of living organisms, he created the doctrine of biological feasibility. Examples of expediency are the development of organisms from seed, the mutual adaptability of organs, the active instincts of animals, and so on.
For a long time, Aristotle's biological works served as a source for zoology. He created a classification and described many species of animals. The scientist was the first to describe the embryonic development of dolphins and whales, as well as the distinctive features of fish. Because of these achievements, some scientists believe that Aristotle is the father of biology.
What are Aristotle's contributions to psychology?
Aristotle is considered the founder of psychology. His treatise “On the Soul” has long been a guide to psychology. In general, this was the first psychological work. He believed that the soul is not a substance, as previously thought. Also, the scientist, unlike the idealist philosophers, argued that the soul is inseparable from matter or the living body. The soul, according to Aristotle, is the essence of living bodies.
What are Aristotle's contributions to medicine?
Aristotle was responsible for introducing the term “aorta” into scientific circulation. He also described the pulmonary aorta. He believed that the human heart has three chambers and is the most important organ in the body. Therefore, being so important for the body, it cannot become seriously ill. Aristotle introduced the concept of decay. He devoted a lot of time to observing temperature changes, seasons and the environment, characterizing them as the causes of certain diseases.
What are Aristotle's contributions to logic?
Aristotle is called the father of the science of logic, which studied the forms of thinking as cognitive activity. He introduced the concepts of contrarian, contradictory and cognitive opposites. The scientist was the first to describe some logical operations, formulate the laws of contradiction, exclusion of thirds and thinking.
What is Aristotle's contribution to educational science?
Aristotle's contribution to pedagogy is characterized by the fact that the ancient figure created an educational institution in Athens called the Lyceum. He headed the educational institution for 12 years. During this period, he wrote many essays, which were the basis for lectures and conversations between the teacher and his students. The main topic of pedagogical conversations was that a person has 3 souls - plant, animal and rational. Therefore, issues of education concerned equal concern for these 3 types of soul. His views on education and upbringing are most fully described in the treatise “Politics”.
What are Aristotle's contributions to natural science?
He outlined his knowledge in the field of natural science in the works “Physics”, “Meteorology”, “On Origin and Destruction”, “Description of Animals”, “On the Soul”, “On Heaven”. He systematized the enormous natural scientific material collected by Aristotle and his predecessors. The systematization was carried out on the basis of a critical analysis of hereditary information, our own observations and a philosophical approach.
What are Aristotle's contributions to rhetoric?
Aristotle is the author of the treatise “Rhetoric,” which he devoted to the art of persuasion. It was written in 355 BC. It is still used today by teachers, politicians and media personalities. The author of the treatise focuses on 5 important lessons that should be learned by anyone who wants to master the art of rhetoric and persuasion that they are right. So, the lessons of Aristotle:
- the proof is in the head
- train logic
- taking “passions” under control
- talking about “beautiful”
- preparation - speech - victory
Aristotle's contribution to history
Scientists rely on his work “The Athenian Polity” in studying the political system of the state of Athens and the system of government of its rulers.
Aristotle's contributions to physics
In the treatises “On Heaven”, “Physics”, “Meteorology” and “On Origin and Destruction”, the scientist gives answers to some physical questions that concern him. He was the first to recognize the fact that physics exists only thanks to a certain system of rules. With their help, knowledge about nature is obtained.
Aristotle is considered the founder of physics. After all, he was responsible for the development of many physical hypotheses and theories. And he also introduced the term “physics” into scientific circulation. The scientist combined and systematized knowledge about nature and created a physical and cosmological picture of the world.
What are Aristotle's contributions to geography?
Aristotle was the first to characterize the nature of the ocean and earth and explain the cycle of water whirlpool in nature. He also described the action and nature of earthquakes, winds, rays, thunder and rainbows, meteors and comets, and the Milky Way. The scientist argued that the formation of the Earth occurs gradually and is so extended in time and space that a person is not able to notice these changes.
Aristotle's contribution to ecology
He wrote the treatise “The History of Animals” and made a description of more than 500 species of animals known to him. Aristotle also spoke about the behavior of animals. Thus, Aristotle’s work characterized the first stage in the development of ecology - the stage of accumulation of factual material and the first attempts to systematize knowledge.
What is Aristotle's contribution to culture?
The cultural heritage of the scientist is represented by two types of works:
- “exoteric” writings – intended for the general public
- “esoteric” - lecture material for students who have spent more than one day at school
We hope that from this article you learned what contribution Aristotle made to the development of science.
The king, whose son subsequently invited the future philosopher to mentor the young Alexander the Great. Aristotle studied with Plato, and after parting with his pupil, he founded his own school, the Lyceum, which is about thirteen years old. During this time, the philosopher wrote several major works: “Metaphysics”, “Physics”, “On the Soul”, “Ethics”, “Poetics”, “Organon”, “History of Animals” and others.
Most of his treatises are devoted to philosophy, despite the different titles. Philosophy in Ancient Greece was the science of existence and studied all phenomena in life. Aristotle distinguished three of its directions - poetic, theoretical and practical. He argued that all things consist of two principles: matter and form. Matter is the substance of which something is composed, and form is the idea, the active principle that organizes matter. At first, his reasoning was characterized by dualism, but later Aristotle became a follower of idealism and believed that form dominates matter.
Aristotle believed that in any science, research should begin with the study of individual things using sensory perception. He was a supporter of induction - movement from the particular to the general, but warned against making hasty conclusions. Aristotle delved into metaphysics for four reasons: material, formal, goal and motive.
Aristotle's influence on the development of science
Aristotle's views and teachings were valued not only during his lifetime, but also for centuries after. He was respected by Arab philosophers of subsequent centuries, scholastics of the Christian Middle Ages treated him with reverence, and humanists who rejected scholastic teaching valued his works even more.
Aristotle is considered the godfather of physics; his treatise “Physics” laid the foundation for the history of this science, although most of its content relates to philosophy. However, he correctly defined the tasks of physics - to study the causes, principles and elements of nature (that is, the fundamental laws, principles and fundamental particles).
Aristotle laid the foundations for the development of chemistry; with his teachings about the four principles - earth, air, water and fire - the pre-alchemical period in the history of this science began. The ancient Greek philosopher suggested that each beginning represents a state of primary matter, but has a certain set of qualities. This idea began to subsequently develop in the Middle Ages.
Aristotle had a huge influence on logic: he studied deductive conclusions, described the logical laws of contradiction, identity and excluded middle. This scientist made a particularly great contribution to philosophical science, defining the views of the Middle Ages and modern times. He also influenced the development of psychology, economics, politics, rhetoric, aesthetics and other areas of scientific knowledge. His works have been translated into Latin, Arabic, French, Hebrew, English and other languages.
Aristotle is the founder of biology as a science. As an astronomer, Aristotle was a systematizer and popularizer, and not the best one at that. As a biologist he is a pioneer.
Since we are writing about Aristotle as a philosopher, it is important for us here to emphasize first of all the philosophical significance of Aristotle’s biological views.
After all, it was a living organism, and not just a person and his activities, as mentioned above, that was a model for Aristotle when constructing a general picture of the world. The doctrine of the final cause with its side companion - spontaneity - was modeled by the philosopher on a living organism in the same way as the same doctrine about the same cause with its side companion - chance - was modeled on the choosing, decision-making person. The world as a whole, with its self-thinking thinking - God, is likened by Aristotle to a thinking living organism. Apology of biology. Before Aristotle, biology was shunned. The stars were more respected objects, nobler material for observation and reflection, than living organisms filled with mucus and feces. Therefore, it is no coincidence that in the first book, “On the Parts of Animals,” Aristotle proves that plants and animals represent an object no less valuable for scientific research than celestial bodies, although the former are transitory, and the latter, as it seemed to the philosopher, are eternal. Speaking about both astronomy and biology, Aristotle proclaims that “both studies have their own charm” (On the parts of animals 1, 5) Moreover, the plant and animal world surrounding humans is given to us in direct sensation in a much greater degrees than celestial bodies, so studying it is a rewarding task, because “we have a greater opportunity to know about animals and plants, because we grow up with them” (ibid.) and are in a natural relationship with them.
Although Aristotle himself felt disgust and disgust for the entrails of animals, for otherwise he would not have said that “one cannot look without great disgust at what a person is made of, such as blood, veins and similar parts” (I , 5), he nevertheless contrasted this feeling, characteristic of many people and frightening them from studying biology, with the pleasure of knowledge, regardless of whether the object of knowledge is pleasant or not to the person’s immediate feeling, if, of course, this person is a true scientist and, especially, a philosopher. After all, “by observing even those of them that are unpleasant to the senses,” says Aristotle, “the nature that created them gives ... inexpressible pleasures to people capable of knowing reasons and philosophers by nature” (I, 5). In the knowledge of causes, as we have seen, Aristotle believed the essence of scientific knowledge and the highest manifestation of the human mind.
At the same time, Aristotle notes that he cannot understand why people prefer the contemplation of artificial images of works of nature than the observation of living originals, which can reveal the causal background of what is observed (which is impossible in the case of dead images).
This consideration also applies to Aristotle’s aesthetic position. Let us note here that Aristotle gives preference to the observation of life over the aesthetic pleasure of contemplating its dead reflection in art. Aristotle calls the widespread “perversion” “strange and contrary to reason.”
Consequently, we have before us an apology for the real observation of living nature. It contradicts the above-mentioned speculative method of Aristotle’s physics and, even more so, his entire metaphysics. This makes one wonder whether the German researcher Jaeger was right, who, trying to solve the Aristotelian question, proceeded from the assumption that the development of Aristotle’s views followed the main line of his elimination of Platonism, and therefore Aristotle’s biological works with their empirical method complete the philosopher’s work. This consideration is also confirmed by the fact that after Aristotle, concrete and even empirical research prevailed in his school - primarily the botany of Theophrastus and others. But the objection is that Aristotle described and mentioned mainly those animals that lived in the Eastern Mediterranean, where the philosopher was in the second period, and therefore Aristotle himself begins with biological works, which had a great influence on his doctrine of the essence of being (formulated on the basis of the model of a living species), and even more so on the teleological nature of his worldview, also, however, significantly.
The empiricism of Aristotle the biologist reaches its apotheosis in his advice not to neglect anything when studying nature: “One should not childishly neglect the study of insignificant animals, for in every work of nature there is something worthy of surprise” (I, 5). Aristotle recalls the words of Heraclitus, addressed by him to the strangers who had arrived to meet him, who hesitated on the threshold of his hut, seeing him warming himself by the weak fireplace and were embarrassed by such a pitiful situation with such a great philosopher. Noticing their confusion, Heraclitus calmly told them to enter boldly, “for the gods dwell here too.” Aristotle applies these legendary words of the great thinker to all natural phenomena, albeit, at first glance, the most insignificant due to their smallness. The worm is no less divine than Sirius.
Here Aristotle is deeply right. The point is not the divinity of the worm, but the fact that the smallest organisms are the most powerful, and the damage that some insignificant Koch stick still inflicts on people is incomparable in magnitude with the damage caused to people by the “kings of nature.” However, humanity, until the invention of the elementary microscope by Leeuwenhoek, knew nothing about the simplest organisms!
So, Aristotle convinces his listeners to abandon their prejudice before the study of living nature, as a low and unworthy task (and this is the same author who in “Politics” proves that virtuosity in art is the work of slaves, while a noble one just needs to play well, so how any virtuosity enslaves a person). Aristotle said in his lectures on biology: “We must approach the study of animals without any disgust, since they all contain something natural and beautiful” (I, 5).
Teleology. However, we should not close our eyes to the fact that our philosopher sees beauty in living nature not in the matter of which living beings are composed (it is this that causes disgust), but in the contemplation of expediency. Aristotle prefers nature to art because “in works of nature, “for the sake of” the beautiful is manifested to an even greater extent than in works of art” (I, 1), constituting a “reasonable basis” in nature (I, 1). Aristotle thus went along the line of an imaginary explanation of the phenomena of living nature, along the line of discovering imaginary causes. After all, the search for a rational basis, a goal, gives the illusion of knowledge. Not more. Of course, in a living organism, where everything is interconnected and where parts exist for the sake of the whole, where many things are subordinated to the whole, everything leads to the question: “For what?” This question in itself is appropriate. However, frozen in such a position, it is easy to slip into the appearance of an explanation. Subsequently, vulgarized Aristotelianism greatly hindered the development of biological science, more than once leading it astray in search of imaginary goals.
Definition of life. Although Aristotle extends his principle of expediency to the entire universe, he is not a hylozoist. Not all bodies are endowed with life. In his work “On the Soul,” Aristotle writes that “of natural bodies, some are endowed with life, others are not” (II, 1). Aristotle has the first definition of life: “We call life all the nourishment, growth and decay of the body that has its basis in itself” (ibid.).
Origin of life. This question must be divided into two aspects: philosophical (metaphysical) and biological (scientific). All types of living things, being forms, are eternal, and therefore in the metaphysical sense life did not begin, since nothing happens at all in the world at the level of “essences of being.” From a biological point of view, the origin of life is quite possible, if by this we mean the implementation (entelechy) of a species in nature. For this there must be favorable conditions. Once realized, the species continues to reproduce itself, a new individual arising from the seed of the older one. However, Aristotle allowed the spontaneous generation of lower species of living things from non-living things: worms, mollusks and even fish, which in terms of metaphysics means that the form of these creatures can become entelechy directly in marine or decaying matter. This false theory of spontaneous generation - the product of a lack of observation in relation to the small things accessible to the naked eye, the study of which Aristotle himself advocated - caused great harm to biology, taking root over time to such an extent that it was only with great difficulty that it was abandoned only in the last century, when experimentally it was possible to it has been proven that specific life is always transmitted through an egg (as for the origin of life in general, this question is still not resolved).
Classification of animals. In the field of biology, Aristotle is the father, first of all, of zoology (like Theophrastus of botany). In Aristotle's zoological works, more than five hundred species of animals were mentioned and described - a huge figure for that time. Aristotle's focus is on the species, not the individual or the genus. These are the “essences of being,” forms, the first essences (according to “Metaphysics”). A species is that minimally general thing that almost merges with the individual, spreading out in it thanks to random, unimportant features, but which still allows definition as a verbal expression of the autonomous “essence of being,” essence in its understanding by Aristotle.
A species is more real than its constituent individuals and than the genus into which the species is included along with other species, for the genus does not really exist; it is a hypostatization of essential characteristics inherent in all species of the genus. In biology, Aristotle is right. The individuals there are really not much different from the species; they are all approximately the same. It is possible that in the doctrine of form in his first philosophy, Aristotle was inspired at this point precisely by his biological observations and knowledge. Unfortunately, he equated people with animals, reducing them to a species, denying a certain Socrates any significant differences from a certain Callias.
However, Aristotle did not stop at species. He sought to include them in more general groups. Aristotle divided all animals into blood-bearing and bloodless, which approximately corresponds to the division of living beings by modern scientific biology into vertebrates and invertebrates. We omit here further details of Aristotle's classification of animals.
"Staircase of Creatures" Summarizing the fact of the presence of transitional forms between plants and animals, flora and fauna, Aristotle writes in his essay “On the Parts of Animals”: “Nature passes continuously from inanimate bodies to animals, through those that live, but are not animals” (IV, 5 ). The History of Animals says that nature gradually passes from plants to animals, because regarding some creatures living in the sea, one can doubt whether they are plants or animals; nature also gradually moves from inanimate objects to animals, because plants, compared to animals, are almost inanimate, and compared to inanimate things, they are animate. Those who have more life and Movement are more animated, while some differ in this respect from others by a small amount.
B. XVIII century the Swiss naturalist Bonnet would call this ascent of species a “ladder of creatures.” It was understood evolutionistically: higher stages appeared later in time than lower ones, life ascended over time along these stages. There was nothing like this in Aristotle’s biological views. For him, all levels coexist from time to time, all forms of living nature are eternal and unchanging. Aristotle is far from evolutionism. And yet Charles Darwin claimed that Linnaeus and Cuvier were his gods, but these “gods” are only children compared to “old Aristotle.” Darwin highly valued Aristotle as the founder of biology and as a non-evolutionist who prepared evolutionism with his idea of gradation, the hierarchization of life forms.
Biological discoveries. Specific biological scientific discoveries are also associated with the name of Aristotle. The chewing apparatus of sea urchins is called “Aristotle’s lantern.” The philosopher distinguished between an organ and a function, linking the first with a material cause, and the second with a formal and purposeful one. Aristotle discovered the principle of correlation in the formula: “What nature takes away in one place, she gives to other parts.” For example, having taken away the teeth in the upper jaw, nature rewards it with horns. Aristotle had other discoveries.
Brief biography of Aristotle (BC), ancient Greek philosopher and scientist. Born in Stagira. In 367 he went to Athens and, becoming a student of Plato, for 20 years, until Plato’s death, was a member of the Platonic Academy. In 343 he was invited by the king of Macedonia to raise his son. In 335 he returned to Athens and created his own school there (Lyceum, or Peripatetic school). He died in Chalkis on Euboea, where he fled from persecution on charges of a crime against religion. Aristotle (BC), ancient Greek philosopher and scientist. Born in Stagira. In 367 he went to Athens and, becoming a student of Plato, for 20 years, until Plato’s death, was a member of the Platonic Academy. In 343 he was invited by the king of Macedonia to raise his son. In 335 he returned to Athens and created his own school there (Lyceum, or Peripatetic school). He died in Chalkis on Euboea, where he fled from persecution on charges of a crime against religion.
Aristotle became one of the founders of science, for the first time summarizing the biological knowledge accumulated by humanity before him. He developed a taxonomy of animals, defining a place in it for man, whom he called “a social animal endowed with reason.” Many of Aristotle's works were devoted to the origin of life. He formulated the theory of continuous and gradual development of living and nonliving matter.
Works of the scientist The works of Aristotle that have reached us are divided according to their content into 7 groups: Logical treatises; Logical treatises; Biological treatises: “History of Animals”, “On the Parts of Animals”, “On the Origin of Animals”, “On the Movement of Animals”; Biological treatises: “History of Animals”, “On the Parts of Animals”, “On the Origin of Animals”, “On the Movement of Animals”; Treatise “On the Soul”; Treatise “On the Soul”; Essay on “first philosophy”; considering existence as such and which later received the name “Metaphysics”; Essay on “first philosophy”; considering existence as such and which later received the name “Metaphysics”; Ethical works - the so-called “Nicomachean Ethics” (dedicated to Nicomacheus, the son of Aristotle) and “Eudemus Ethics” (dedicated to Eudemus, a student of Aristotle); Ethical works - the so-called “Nicomachean Ethics” (dedicated to Nicomacheus, the son of Aristotle) and “Eudemus Ethics” (dedicated to Eudemus, a student of Aristotle); Socio-political and historical works: “Politics”, “The Athenian Polity”. Socio-political and historical works: “Politics”, “The Athenian Polity”.
Aristotle's Biology In the field of biology, one of Aristotle's merits is his doctrine of biological expediency, based on observations of the expedient structure of living organisms. In the field of biology, one of Aristotle’s merits is his doctrine of biological expediency, based on observations of the expedient structure of living organisms. Aristotle saw examples of expediency in nature in such facts as the development of organic structures from a seed, various manifestations of the purposefully acting instinct of animals, the mutual adaptability of their organs, etc. Aristotle saw examples of expediency in nature in such facts as the development of organic structures from a seed, various manifestations of the expediently acting instinct of animals, the mutual adaptability of their organs, etc. In the biological works of Aristotle, which for a long time served as the main source of information on zoology, a classification and description of numerous species of animals was given. In the biological works of Aristotle, which for a long time served as the main source of information on zoology, a classification and description of numerous species of animals was given. The matter of life is the body, the form is the soul, which Aristotle called “entelechy.” The matter of life is the body, the form is the soul, which Aristotle called “entelechy.” According to the three kinds of living beings (plants, animals, humans), Aristotle distinguished three souls, or three parts of the soul: plant, animal (sensing) and rational. According to the three kinds of living beings (plants, animals, humans), Aristotle distinguished three souls, or three parts of the soul: plant, animal (sensing) and rational.
Animal taxonomy The animal system was first developed in the 4th century. BC e. Aristotle, who described more than 450 forms, dividing them into 2 large groups: - animals supplied with blood (vertebrates, according to modern ideas); -bloodless (invertebrates, in the modern sense). -bloodless (invertebrates, in the modern sense). Animals with blood, in turn, were divided by him into groups roughly corresponding to modern classes. With regard to invertebrates, Aristotle's system was less perfect. Thus, among modern types, he more or less correctly identified only arthropods. With regard to invertebrates, Aristotle's system was less perfect. Thus, among modern types, he more or less correctly identified only arthropods.
The theory of spontaneous generation of living beings In his works, Aristotle cites countless “facts” of spontaneous generation of living beings of plants, insects, worms, frogs, mice, some sea animals, indicating the necessary conditions for this in the presence of decomposing organic remains, manure, spoiled meat, various garbage, dirt . Aristotle even provided a certain theoretical basis for these “facts”; he argued that the sudden birth of living beings was caused by nothing more than the influence of some spiritual principle on previously lifeless matter.
But at the same time, Aristotle also expresses quite sound thoughts, close in essence to evolutionary theory: “In addition, it is possible that some bodies from time to time transform into others, and those, in turn, decaying, undergo new transformations, and thus In this way, development and decay balance each other.”
Aristotle's ladder It is also certainly worth noting that Aristotle was the first scientist to express the idea of a “ladder of creatures” (from the less developed and more primitive to the most developed, and in a broader sense from inanimate nature to living). This is what Aristotle's "ladder" looked like: This is what Aristotle's "ladder" looked like: 1) Man; 2) Animals; 2) Animals; 3) Zoophytes; 3) Zoophytes; 4) Plants; 5) Inorganic matter.
He defended a dissertation in which he tried to find the “laws of generation” of all organic bodies, and in accordance with this, he successively considered in it “the generation of plants,” “the generation of animals,” and, finally, “the general laws of the generation of organic bodies.” Wolf made an important discovery while studying the development of stems, leaves and flowers. He discovered that at the top of each growing shoot there is a special "point or surface of growth." Before Wolff, the process of “unfolding” (evolutio) of bud, flower and leaf was a classic example of preformation. Wolf's assertion that inside every leaf bud there are no noticeable leaves, but only the “internal substance of plants”, which gives rise to the rudiments of leaves, was the starting point of a new principle of development. Another important discovery is made by K.F. Wolf, tracing the development of the flower. His doctrine of plant metamorphosis was completed in his work of the St. Petersburg period (1767), in which he states: “In the entire plant, the parts of which at first glance are so unusually diverse, I see, after a mature examination, nothing more than leaves and stems... "All parts of the plant, with the exception of the stem, are therefore only modified leaves." This doctrine of plant metamorphosis is the indisputable historical merit of K.F. Wolf. He also observed the development of an incubated chicken egg. He discovered the formation of "blood islands", which then turn into blood and blood vessels; he described the formation of limbs, primary kidneys and a number of other organs. These are Wolf's observations in brief, which allowed him to reject the theory of preformation and put forward the idea of the true development of plants and animals. In 1767, Wolf came to Russia, and in September of the same year he presented his new work “On the formation of the intestines in the chicken” for publication. This is the most mature work of K.F. Wolf - a strictly scientific treatise, in which he refrains from hasty natural-philosophical generalizations; he formulates the general principle of the development of organs: “The part which, when completed, has an internal cavity or represents a tube or reservoir, in its original state was open and stretched in the form of a certain kind of simple plate, the edges of which were forced to fold together to form whole channel." K.F. Wolff tirelessly repeated that the patterns he discovered were “the main evidence of epigenesis.” Thanks to the collection of the Kunstkamera, he wrote numerous anatomical works, published annually for 25 years in the proceedings of the St. Petersburg Academy and wrote at least 1000 pages of descriptions of monsters that were particularly interesting, from his point of view, still unpublished.