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- Herausgeber: Booksell-Verlag
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
In "On the Generation of Animals," Aristotle delivers a profound exploration of reproductive processes and the development of life forms, intertwining empirical observation with philosophical inquiry. Employing a systematic and analytical literary style, Aristotle meticulously categorizes various modes of generation, from oviparity to viviparity, and delves into the roles of form and matter in the essence of living beings. This work not only contributes to the natural sciences but also reflects the Aristotelian commitment to categorization and causation, emblematic of his broader philosophical paradigm, bridging metaphysics and biological observation in a way that would influence generations of thinkers. Aristotle, a towering figure of ancient Greek philosophy, was shaped by his unique experiences as a student of Plato and later as a teacher at the Lyceum. His extensive studies of nature, ethics, and metaphysics led him to investigate the biological underpinnings of life. "On the Generation of Animals" stands as a testament to his dedication to observing the natural world with rigor, driven by an insatiable curiosity that highlighted the interplay of biology and philosophy throughout his life. This foundational text is essential for modern readers who seek to understand the origins of biological thought and the evolution of scientific inquiry. It intricately reveals Aristotle's innovative approach, inviting readers to appreciate the depth of his observations and their lasting impact on both philosophy and biology, making it a must-read for anyone interested in the intersections of life, science, and thought. In this enriched edition, we have carefully created added value for your reading experience: - A succinct Introduction situates the work's timeless appeal and themes. - The Synopsis outlines the central plot, highlighting key developments without spoiling critical twists. - A detailed Historical Context immerses you in the era's events and influences that shaped the writing. - An Author Biography reveals milestones in the author's life, illuminating the personal insights behind the text. - A thorough Analysis dissects symbols, motifs, and character arcs to unearth underlying meanings. - Reflection questions prompt you to engage personally with the work's messages, connecting them to modern life. - Hand‐picked Memorable Quotes shine a spotlight on moments of literary brilliance. - Interactive footnotes clarify unusual references, historical allusions, and archaic phrases for an effortless, more informed read.
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Veröffentlichungsjahr: 2021
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On the Generation of Animals
Table of Contents
Introduction
"The nature of animals is to begin at their end and to reach for the beginning; this cyclical existence is essential to their understanding." This profound observation from Aristotle in On the Generation of Animals encapsulates the complex relationship between birth, growth, and life. As one of the foundational texts in biological philosophy, it prompts readers to contemplate the underlying principles that govern living beings, thereby engaging them in an exploration of nature that is as thought-provoking today as it was over two millennia ago.
On the Generation of Animals is considered a classic not merely because of its age but due to its infinite depth in understanding the biological processes that underpin life. Aristotle’s meticulous observations and systematic categorizations provided a framework for a multitude of future disciplines, including biology, philosophy, and ethics. The elegance of his prose, coupled with the weight of his insights, has enabled the text to stand the test of time, influencing thinkers from the ancient Greek philosophers to modern scientists.
Written around the 4th century BCE, this seminal work belongs to the early corpus of Aristotle's biological texts. It represents his efforts to make sense of the natural world, particularly focusing on the reproduction, growth, and anatomy of animals. Evidence of his keen observational skills is readily apparent, allowing him to classify species and articulate their functions and interactions. Through this, Aristotle's purpose was to demystify the processes of life, providing a logical exposition that reflected his philosophical ideals.
Aristotle, often regarded as the father of Western philosophy, embarked on a journey of inquiry that led him to question the essence of life itself. In On the Generation of Animals, he delves into the concepts of form and matter, recognizing the interplay between them as central to understanding how animals come into being. His meticulous analysis serves not only to illustrate his findings but also represents an approach that values empirical observation and rational thought.
The text tackles significant questions related to generation, differentiation, and the relationships among various species. Aristotle’s inquiry takes into account the common experiences of life, the distinctions that set species apart, and the overarching laws that govern their existence. In doing so, he paves the way for future exploration of evolutionary theory by illustrating not only the complexity of life but also its inherent simplicity, thereby setting the stage for generations of biology after him.
In addition to its biological insights, the book weaves in philosophical discourse about the essence of life. Aristotle critiques the prevailing theories of his time, juxtaposing them against his empirical observations. This willingness to confront established paradigms allows the reader to appreciate his role in intellectual history, showing that questioning and observation are vital tools for understanding reality. Such intellectual courage still resonates, echoing in contemporary scientific discourse.
The combination of Aristotle's philosophical thoughts with empirical observations marks On the Generation of Animals as a pioneering text that transcends mere academic study. It invites reflection not just on biological phenomena, but also on the ethical dimensions of those phenomena. The inherent value of all living creatures and the importance of their roles within the ecosystem come to life, urging readers to consider their relationship to nature more deeply.
Throughout the text, Aristotle's descriptive prowess brings to light the myriad complexities of animal generation. Whether discussing the miraculous process of reproduction or the variations across species, he encapsulates life in a manner that feels vivid and immediate. For modern readers, this lends a sense of intimacy and urgency to his studies, making these ancient observations feel relevant and engaging in today's context.
While Aristotle's teachings may have been revolutionary for their time, they remain an integral part of the canon of Western thought and continue to inspire scientists, philosophers, and writers alike. His ability to combine observation with rational inquiry serves as a model for rigorous scholarly work. Consequently, readers can glean methods for conducting their investigations into the natural world, regardless of the specific disciplines they pursue.
On the Generation of Animals engages with themes that range far beyond the mere biological. It explores the interconnectedness of life, the cyclical nature of existence, and the philosophical inquiry into what it means to be alive. This wide-ranging focus ensures that it remains pertinent across diverse fields, from environmental ethics to modern biology, and positions it as a text that every curious mind should encounter.
As a legacy of Aristotle's intellectual journey, On the Generation of Animals emerges as a crucial articulation of natural philosophy. It is not solely a catalog of observations, but rather a rich tapestry of insights woven together by the threads of curiosity and rationality. The lasting influence of Aristotle resonates through time, as new generations continue to draw inspiration from both his questions and conclusions.
Furthermore, the work serves as a crossroads where literature and science meet, illustrating the importance of narrative in scientific discourse. It captivates readers with its rich language and vivid descriptions, marrying the poetic qualities of literature with the precision of scientific inquiry. This unique blend ensures that On the Generation of Animals remains not just a work of philosophy, but also a captivating read.
The principles outlined in this text reverberate in modern discussions regarding biology and genetics today. As the scientific community grapples with rapid advancements and ethical dilemmas in the field of genetic engineering, Aristotle's contemplation of natural forms and their integrity finds renewed relevance. His philosophical premises prompt contemporary audiences to reflect on the direction in which modern science is heading.
Readers who engage with On the Generation of Animals unlock a window into Aristotle's mind, one filled with wonder at the complexities of life. His acute observations lead not only to a deeper understanding of animal generation but also to profound questions that stir deeper contemplation regarding human existence and ethics. Every turn of the page reveals another layer in the intricate fabric of existence, challenging the reader to ponder their own moral and ethical stances in relation to the natural world.
As such, the text invites a continual reexamination of its core themes, pushing readers to cultivate a sense of curiosity and to seek knowledge not just for its own sake, but for its application in the real world. In On the Generation of Animals, Aristotle provides more than mere information; he instills a spirit of inquiry that remains an essential quality in the pursuit of knowledge today.
Ultimately, On the Generation of Animals stands as a timeless reflection on the processes that define life. It is an invitation to explore, investigate, and ponder the workings of the natural world, transforming the reader’s understanding from mere observers to engaged participants in the exploration of existence. This text continues to inspire and challenge the boundaries of thought for both ancient and contemporary audiences alike.
In conclusion, On the Generation of Animals not only holds its place in the annals of classical literature but also serves as a fundamental touchstone for the study of life itself. Aristotle's innovative approach and enduring insights continue to resonate, making this text a vital part of any scholarly exploration into the biological, philosophical, and ethical dimensions of animals and existence. The wisdom contained within beckons readers to engage with the world of nature in all its complexity.
Synopsis
In 'On the Generation of Animals,' Aristotle delves into the biological and philosophical aspects of reproduction and development in various animal species. Written in the fourth century BCE, the text combines observations from his studies of the natural world with foundational concepts of biology. Aristotle's curiosity about how different animals come to be drives his inquiry, leading him to explore themes such as generation, growth, and the differences between male and female organisms. This work serves as a critical scientific framework for understanding animal development during the ancient philosophical period.
The opening sections of the book focus on the broader concept of generation, distinguishing it from mere reproduction. Aristotle emphasizes that generation encompasses the entire process from conception to maturity, discussing how different environmental factors can influence this process. He defines generation in a metaphysical context, highlighting the importance of the potentiality of an animal's form and its actualization. This exploration sets the stage for a deeper examination of how specific reproductive mechanisms operate in various species.
Aristotle categorizes animals based on their modes of generation, particularly noting those that reproduce sexually versus asexually. He places significant emphasis on the role of semen and its contribution to the generation of offspring. By comparing different species, he highlights the variances in reproductive strategies, such as oviparous (egg-laying) and viviparous (live-bearing) organisms. These distinctions inform his understanding of biological diversity and contribute to his argument about the inherent qualities of different animal types and their environments.
The philosopher also provides a detailed analysis of the concept of ‘form’ and ‘matter’ in relation to generation. He utilizes the metaphysical frameworks of potentiality and actuality to explain how an animal's form is determined by its parentage. The union of male and female contributions during conception is meticulously discussed, and Aristotle posits that the male's semen serves not just as a vehicle for life but also carries the essence that defines the offspring's nature.
As the text progresses, Aristotle examines the development stages of embryos, offering descriptions of their formation in various organisms. His observations include the stages of development, from initial formation to the eventual birth or hatching of the animal. He emphasizes the importance of nutrition and environmental conditions in fostering healthy development. Through these insights, he provides a foundational understanding of embryology that would influence later biological studies.
In his exploration of animals' diverse reproductive strategies, Aristotle takes care to discuss the peculiarities of certain species. For instance, he investigates the reproductive habits of insects, fish, and mammals, noting the complexity that arises in their generative processes. He also reflects on the phenomena of parthenogenesis and the extraordinary nature of certain organisms that can reproduce without fertilization. This detailed observation showcases Aristotle's rigorous empirical methodology, combining theory with practical inquiry.
The text also addresses the hereditary properties of traits and the transmission of characteristics from parents to offspring. Aristotle concludes that offspring inherit qualities from both parents, and he investigates the mechanisms behind these traits, albeit limited by the scientific knowledge of his time. His ideas would later lead to foundational concepts in genetics, highlighting the importance of lineage and the continuity of life forms throughout generations.
By the conclusion of 'On the Generation of Animals,' Aristotle synthesizes his findings, reiterating the importance of understanding animal generation not only for scientific inquiry but also for appreciating the essence of life itself. He ties together the themes of potentiality and actuality, emphasizing the interconnectedness of form, function, and environment in the process of generation. This holistic approach marks a significant advancement in the study of biology and natural philosophy.
Ultimately, 'On the Generation of Animals' serves as a crucial text bridging biology and philosophy. Aristotle's systematic study of animal generation has laid the groundwork for future biological exploration. By merging observation with theoretical reasoning, he establishes a framework for understanding the complexities of life. Through this work, Aristotle not only contributes to the discourse on biology but also invites readers to contemplate the grandeur of life and the processes that sustain it.
Historical Context
On the Generation of Animals was composed by Aristotle around 350 BCE, likely during his years in Athens, where he had established the Lyceum. Its origins lie in the Classical Era of Greece, a period noted for advances in philosophy, arts and sciences. Athens, long regarded as a center of political and intellectual life, offered a setting in which public debate and scholarly activity flourished. Aristotle, having studied at Plato’s Academy, both drew on and moved beyond his teacher’s ideas, developing his own approach to the study of living beings.
Earlier in the 5th century BCE, the Persian Wars (490–479 BCE) had united various Greek city-states against external threats and contributed to a shared sense of Hellenic identity. Though Aristotle wrote nearly a century later, the spirit of inquiry that emerged in their aftermath persisted, fostering environments where questions of nature and causation could be pursued. In the treatise on animal generation, he emphasizes observable processes—embryonic development, nutrition and growth—rather than speculative myth.
The democratic institutions of Athens, established in the 5th century BCE, encouraged free exchange of ideas and collective decision-making. In this climate, Aristotle applied systematic observation and logical analysis to his biological studies. He arranges species in groups based on common characteristics and investigates the roles of male and female in reproduction, illustrating a methodical effort to classify and explain phenomena in the natural world.
The Peloponnesian War (431–404 BCE) and its aftermath altered Athens’ political landscape, yet intellectual life continued within the city’s schools and gardens. While the experience of conflict may have shaped general reflections on change and stability, the treatise itself remains focused on detailed comparisons of anatomical and developmental features across animals.
In the mid-4th century BCE, Philip II of Macedon extended Macedonian influence over the Greek city-states, and later his son Alexander carried Greek culture far beyond the Aegean. Aristotle’s biological investigations antedate the great conquests of Alexander, but the broader world of increasingly diverse environments and new species may have underscored the value of systematic study.
The work reflects a wider shift within natural philosophy: earlier thinkers such as Thales and Anaximander had begun to seek material explanations for natural phenomena, and Aristotle built on this trend by insisting on careful observation and coordinated classification. His commitment to hylomorphism—the idea that form and matter constitute substances—underpins his analysis of generation and growth.
Aristotle’s discussion of reproductive roles reflects the gender assumptions of his time, in which women were generally seen as secondary in public and intellectual life. His descriptions of the relative contributions of male and female align with prevailing notions of active and passive principles, rather than a modern perspective on equality.
Slavery was widely practiced in classical Athens, and hierarchical thinking extended into scientific classification. In examining the gradations of life forms, Aristotle applies a principle of scale or “scala naturae,” ordering creatures according to complexity—an approach consistent with social as well as biological hierarchies of the era.
Although his biological treatises differ in purpose from the ethical and political works in which he justifies slavery or discusses virtue, they share a methodological insistence on causes—material, formal, efficient and final. The legacy of Socratic questioning and Platonic influence remains in his concern for definition, but he grounds his inquiry firmly in empirical evidence.
Aristotle founded the Lyceum as a center for collaborative research and teaching, and this institutional context shaped his investigations. The treatise on animal generation exemplifies the emerging role of formal education in systematic study, advocating a scientific approach that combines field observation with organized debate.
Contemporary advances in engineering, medicine and astronomy provided tools and models for biological research, and Aristotle’s methodology reflects a transition from mythological accounts to practical investigations of anatomy and reproduction. His work on animal generation thus marks a significant milestone in the history of natural science.
The intellectual contrast with Plato’s theory of transcendent forms is evident in Aristotle’s emphasis on the material world. By focusing on observable processes and concrete classifications, he lays the groundwork for later developments in taxonomy and embryology. Even as political systems shifted around him—from democracy to oligarchy, from city-state rivalry to Macedonian hegemony—his systematic study of life remained anchored in careful observation and logical inference.
Author Biography
Introduction
Aristotle of Stagira was a philosopher and polymath whose writings shaped logic, metaphysics, ethics, politics, biology, psychology, rhetoric, and literary theory. A student of Plato and later tutor to Alexander of Macedon, he founded the Lyceum in Athens and led the Peripatetic school, advancing a research culture that combined rigorous argument with empirical observation. His major works include the Nicomachean Ethics, Politics, Metaphysics, Physics, De Anima, Rhetoric, and Poetics, as well as the logical corpus later called the Organon. Across antiquity, the medieval world, and into the present, Aristotle’s ideas have remained foundational to intellectual history and education.
Education and Literary Influences
Aristotle was born in Stagira in the 4th century BCE. His father, traditionally identified as a physician connected to the Macedonian court, likely shaped his early familiarity with biological observation and medical reasoning. As a youth he traveled to Athens and entered Plato’s Academy, where he studied and taught for many years. The Academy’s discipline of dialectic, its commitment to systematic inquiry, and its intense engagement with metaphysical questions deeply formed Aristotle’s intellectual habits. Although he diverged from Platonic doctrines, the Academy’s emphasis on definition, argument, and the pursuit of the good provided the framework within which he developed his own philosophy.
Aristotle’s sources of inspiration were broad and meticulously examined. He engaged critically with Plato’s theory of Forms, reworking it into a hylomorphic account of beings as composites of form and matter. He studied the arguments of earlier natural philosophers—Parmenides, Heraclitus, Empedocles, Anaxagoras, and Democritus—adapting and refuting them to build his own natural philosophy. The rhetorical culture of Greece and debates among Sophists informed his Rhetoric, just as Attic tragedy and epic poetry provided material for the Poetics. His attention to observational detail, strengthened by medical and biological traditions, helped unify speculative reasoning with systematic collection and classification of facts.
Literary Career
After Plato’s death in the mid-4th century BCE, Aristotle left Athens. He spent time in Asia Minor, associated with Assos under the ruler Hermias, and conducted intensive biological research on Lesbos. This period saw collaboration with Theophrastus, later his successor, and the development of a method attentive to detailed observation. Summoned to Macedon, he served as tutor to the young Alexander, a role that enhanced his stature but also linked him to political currents of the era. Returning to Athens, Aristotle founded the Lyceum, where he organized research programs, lectures, and collections, building a community that investigated nature, ethics, politics, and language.
Aristotle’s logical writings, later grouped as the Organon, include the Categories, On Interpretation, Prior Analytics, Posterior Analytics, Topics, and Sophistical Refutations. Together they present a system of terms, propositions, and syllogistic inference, culminating in a theory of demonstration that ties scientific knowledge to explanatory causes. His style favors careful distinctions, precise definitions, and layered arguments, often moving from common opinions to refined analysis. The logical corpus furnished scholars for centuries with a toolkit for rigorous reasoning, shaping the structure of inquiry in philosophy, theology, and science well into the medieval period and beyond.
In ethics and politics, Aristotle explored the cultivation of virtue, the nature of happiness (eudaimonia), and the organization of civic life. The Nicomachean Ethics and the Eudemian Ethics analyze character, practical wisdom, friendship, and the “mean” as a guide to moral excellence. The Politics studies constitutions, citizenship, education, and the common good, drawing on comparative evidence and case studies. Within his school, researchers compiled materials on many city-states, including the Constitution of the Athenians, reflecting his commitment to empirical grounding. These works influenced ancient debates about the best regimes and continue to inform discussions of virtue ethics and political theory.
Aristotle’s natural philosophy treats change, motion, and causation in the Physics and the cosmos in On the Heavens. His biological inquiries—History of Animals, Parts of Animals, and Generation of Animals—feature extensive observations and classifications. De Anima examines the soul as the form of living beings, integrating psychology with biology. The Metaphysics investigates being as being, essence, and the principles of substance, while the Rhetoric and Poetics analyze persuasion, style, tragedy, and mimesis. Much of the surviving corpus appears to be lecture materials and notes from the Lyceum. Their arrangement is often credited to later editors, including Andronicus of Rhodes.
Beliefs and Advocacy
Aristotle’s philosophy is unified by a commitment to explanation through causes. He articulated four causes—material, formal, efficient, and final—and a hylomorphic view in which form and matter jointly constitute substances. His metaphysics emphasizes potentiality and actuality, enabling accounts of development and change without abandoning intelligible structure. In epistemology, Aristotle grounded science in demonstration from first principles, themselves grasped through refined experience and intellect. He presented logic as an instrument for inquiry rather than an end in itself. This framework supports his view that knowledge aims at understanding why things are as they are, integrating observation with conceptual analysis.
In ethics, Aristotle advanced a virtue-based approach where character is shaped by habituation, practical wisdom orients choice, and happiness is an activity in accordance with virtue. He regarded contemplation as a high fulfillment of human capacities. In politics, he argued that the polis exists by nature and aims at the good life, with education and law cultivating citizens’ virtues. He defended private property while endorsing its use for communal benefit. Parts of his political theory, including a defense of “natural slavery” and views on women’s roles, have been widely criticized by later readers and examined within their historical context.
Although not an advocate in a modern activist sense, Aristotle promoted a civic and intellectual ethos through institutional practice. The Lyceum functioned as a collaborative research center, with students collecting animals, plants, and constitutional data, reflecting his belief that disciplined observation should inform theory and policy. His engagement with rhetoric sought ethical persuasion grounded in character and reason rather than manipulation. His connection to Macedonian power affected perceptions of his public stance in Athens, and his decision to leave the city in turbulent times underscores a prudential concern for philosophy’s survival and the continuity of scholarly inquiry.
Final Years & Legacy
In the years following Alexander’s death, anti-Macedonian sentiment in Athens intensified. Aristotle faced a charge of impiety and withdrew to Chalcis in Euboea, reportedly to prevent the city from “sinning twice against philosophy.” He died there in the early 320s BCE. Theophrastus succeeded him as head of the Lyceum, continuing research and teaching. Over subsequent centuries, Aristotle’s writings were preserved and studied in various centers; the arrangement and wider dissemination of the corpus are often associated with Andronicus of Rhodes. His school’s continuity ensured that Aristotelian methods and doctrines remained active topics of debate and development.
Aristotle’s long-term impact is vast. In the Islamic world, thinkers such as Al-Farabi, Avicenna, and Averroes interpreted and extended his works, transmitting them to medieval Europe. In Latin Christendom, Aristotelian philosophy—especially through Thomas Aquinas—became central to scholastic theology, even after early prohibitions. Early modern science challenged parts of his physics, yet his biology, ethics, and logic continued to stimulate inquiry. Contemporary philosophy draws on his virtue ethics, metaphysics of powers, and accounts of explanation, while literary theory still engages the Poetics. Aristotle’s standing endures as a standard for systematic reasoning and as a resource for interdisciplinary reflection.
On the Generation of Animals
Part 1
WE have now discussed the other parts of animals, both generally and with reference to the peculiarities of each kind, explaining how each part exists on account of such a cause, and I mean by this the final cause[1].
There are four causes underlying everything: first, the final cause, that for the sake of which a thing exists; secondly, the formal cause, the definition of its essence (and these two we may regard pretty much as one and the same); thirdly, the material; and fourthly, the moving principle[4] or efficient cause.
We have then already discussed the other three causes, for the definition and the final cause are the same, and the material of animals is their parts of the whole animal the non-homogeneous parts, of these again the homogeneous, and of these last the so-called elements of all matter. It remains to speak of those parts which contribute to the generation of animals and of which nothing definite has yet been said, and to explain what is the moving or efficient cause. To inquire into this last and to inquire into the generation of each animal is in a way the same thing; and, therefore, my plan has united them together, arranging the discussion of these parts last, and the beginning of the question of generation next to them.
Now some animals come into being from the union of male and female, i.e. all those kinds of animal which possess the two sexes. This is not the case with all of them; though in the sanguinea[2] with few exceptions the creature, when its growth is complete, is either male or female, and though some bloodless animals have sexes so that they generate offspring of the same kind, yet other bloodless animals generate indeed, but not offspring of the same kind; such are all that come into being not from a union of the sexes, but from decaying earth and excrements. To speak generally, if we take all animals which change their locality, some by swimming, others by flying, others by walking, we find in these the two sexes, not only in the sanguinea but also in some of the bloodless animals; and this applies in the case of the latter sometimes to the whole class, as the cephalopoda[3] and crustacea, but in the class of insects only to the majority. Of these, all which are produced by union of animals of the same kind generate also after their kind, but all which are not produced by animals, but from decaying matter, generate indeed, but produce another kind, and the offspring is neither male nor female; such are some of the insects. This is what might have been expected, for if those animals which are not produced by parents had themselves united and produced others, then their offspring must have been either like or unlike to themselves. If like, then their parents ought to have come into being in the same way; this is only a reasonable postulate to make, for it is plainly the case with other animals. If unlike, and yet able to copulate, then there would have come into being again from them another kind of creature and again another from these, and this would have gone on to infinity. But Nature flies from the infinite, for the infinite is unending or imperfect, and Nature ever seeks an end.[1q]
But all those creatures which do not move, as the testacea[5] and animals that live by clinging to something else, inasmuch as their nature resembles that of plants, have no sex any more than plants have, but as applied to them the word is only used in virtue of a similarity and analogy. For there is a slight distinction of this sort, since even in plants we find in the same kind some trees which bear fruit and others which, while bearing none themselves, yet contribute to the ripening of the fruits of those which do, as in the case of the fig-tree and caprifig.
The same holds good also in plants, some coming into being from seed and others, as it were, by the spontaneous action of Nature, arising either from decomposition of the earth or of some parts in other plants, for some are not formed by themselves separately but are produced upon other trees, as the mistletoe. Plants, however, must be investigated separately.
Part 2
Of the generation of animals we must speak as various questions arise in order in the case of each, and we must connect our account with what has been said. For, as we said above, the male and female principles may be put down first and foremost as origins of generation,[2q] the former as containing the efficient cause of generation, the latter the material of it. The most conclusive proof of this is drawn from considering how and whence comes the semen; for there is no doubt that it is out of this that those creatures are formed which are produced in the ordinary course of Nature; but we must observe carefully the way in which this semen actually comes into being from the male and female. For it is just because the semen is secreted from the two sexes, the secretion taking place in them and from them, that they are first principles of generation. For by a male animal we mean that which generates in another, and by a female that which generates in itself; wherefore men apply these terms to the macrocosm also, naming Earth mother as being female, but addressing Heaven and the Sun and other like entities as fathers, as causing generation.
Male and female differ in their essence by each having a separate ability or faculty, and anatomically by certain parts; essentially the male is that which is able to generate in another, as said above; the female is that which is able to generate in itself and out of which comes into being the offspring previously existing in the parent. And since they are differentiated by an ability or faculty and by their function, and since instruments or organs are needed for all functioning, and since the bodily parts are the instruments or organs to serve the faculties, it follows that certain parts must exist for union of parents and production of offspring. And these must differ from each other, so that consequently the male will differ from the female. (For even though we speak of the animal as a whole as male or female, yet really it is not male or female in virtue of the whole of itself, but only in virtue of a certain faculty and a certain part — just as with the part used for sight or locomotion — which part is also plain to sense-perception.)
Now as a matter of fact such parts are in the female the so-called uterus, in the male the testes and the penis, in all the sanguinea; for some of them have testes and others the corresponding passages. There are corresponding differences of male and female in all the bloodless animals also which have this division into opposite sexes. But if in the sanguinea it is the parts concerned in copulation that differ primarily in their forms, we must observe that a small change in a first principle is often attended by changes in other things depending on it. This is plain in the case of castrated animals, for, though only the generative part is disabled, yet pretty well the whole form of the animal changes in consequence so much that it seems to be female or not far short of it, and thus it is clear than an animal is not male or female in virtue of an isolated part or an isolated faculty. Clearly, then, the distinction of sex is a first principle;[4q] at any rate, when that which distinguishes male and female suffers change, many other changes accompany it, as would be the case if a first principle is changed.
Part 3
The sanguinea are not all alike as regards testes and uterus. Taking the former first, we find that some of them have not testes at all, as the classes of fish and of serpents, but only two spermatic ducts. Others have testes indeed, but internally by the loin in the region of the kidneys, and from each of these a duct, as in the case of those animals which have no testes at all, these ducts unite also as with those animals; this applies (among animals breathing air and having a lung) to all birds and oviparous quadrupeds. For all these have their testes internal near the loin, and two ducts from these in the same way as serpents; I mean the lizards and tortoises and all the scaly reptiles. But all the vivipara[6] have their testes in front; some of them inside at the end of the abdomen, as the dolphin, not with ducts but with a penis projecting externally from them; others outside, either pendent as in man or towards the fundament as in swine. They have been discriminated more accurately in the Enquiries about Animals.
