In the philosophy of science, protoscience (adj. protoscientific) is a research field that has the characteristics of an undeveloped science that may ultimately develop into an established science. Philosophers use protoscience to understand the history of science and distinguish protoscience from science and pseudoscience.
The word "protoscience" is a hybrid Greek-Latin compound of the roots proto- + scientia, meaning a first or primeval rational knowledge.
Science in the ancient world encompasses the earliest history of science from the protoscience of prehistory and ancient history to late antiquity. In ancient times, culture and knowledge were passed through oral tradition. The development of writing further enabled the preservation of knowledge and culture, allowing information to spread accurately.
The earliest scientific traditions of the ancient world developed in the Ancient Near East, with Ancient Egypt and Babylonia in Mesopotamia. Later traditions of science during classical antiquity were advanced in ancient Persia, Greece, Rome, India, China, and Mesoamerica. Aside from alchemy and astrology that waned in importance during the Age of Enlightenment, civilizations of the ancient world laid the roots of modern sciences.
The history of science covers the development of science from ancient times to the present. It encompasses all three major branches of science: natural, social, and formal. Protoscience, early sciences, and natural philosophies such as alchemy and astrology that existed during the Bronze Age, Iron Age, classical antiquity and the Middle Ages, declined during the early modern period after the establishment of formal disciplines of science in the Age of Enlightenment.
The earliest roots of scientific thinking and practice can be traced to Ancient Egypt and Mesopotamia during the 3rd and 2nd millennia BCE. These civilizations' contributions to mathematics, astronomy, and medicine influenced later Greek natural philosophy of classical antiquity, wherein formal attempts were made to provide explanations of events in the physical world based on natural causes. After the fall of the Western Roman Empire, knowledge of Greek conceptions of the world deteriorated in Latin-speaking Western Europe during the early centuries (400 to 1000 CE) of the Middle Ages, but continued to thrive in the Greek-speaking Byzantine Empire. Aided by translations of Greek texts, the Hellenistic worldview was preserved and absorbed into the Arabic-speaking Muslim world during the Islamic Golden Age. The recovery and assimilation of Greek works and Islamic inquiries into Western Europe from the 10th to 13th century revived the learning of natural philosophy in the West. Traditions of early science were also developed in ancient India and separately in ancient China, the Chinese model having influenced Vietnam, Korea and Japan before Western exploration. Among the Pre-Columbian peoples of Mesoamerica, the Zapotec civilization established their first known traditions of astronomy and mathematics for producing calendars, followed by other civilizations such as the Maya.
The term cosmography has two distinct meanings: traditionally it has been the protoscience of mapping the general features of the cosmos, heaven and Earth; more recently, it has been used to describe the ongoing effort to determine the large-scale features of the observable universe.
Premodern views of cosmography can be traditionally divided into those following the tradition of ancient near eastern cosmology, dominant in the Ancient Near East and in early Greece.
The chalcogens (/ˈkælkədʒənz/, KAL-kə-jənz) are the chemical elements in group 16 of the periodic table. This group is also known as the oxygen family. Group 16 consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioactive elements polonium (Po) and livermorium (Lv). Often, oxygen is treated separately from the other chalcogens, sometimes even excluded from the scope of the term "chalcogen" altogether, due to its very different chemical behavior from sulfur, selenium, tellurium, and polonium. The word "chalcogen" means "ore-forming"; chalcogens got their name because protoscientists and early scientists could discern that these essences (which science would later reveal to be chemical elements) were involved in ore formation.
Sulfur has been known since antiquity, and oxygen was recognized as an element in the 18th century. Selenium, tellurium and polonium were discovered in the 19th century, and livermorium in 2000. All of the chalcogens have six valence electrons, leaving them two electrons short of a full outer shell. Their most common oxidation states are −2, +2, +4, and +6. They have relatively small atomic radii, especially the lighter ones.