Evidence of the origins of Homo sapiens sapiens, the species in which all humans belong, comes from a small, but increasing, number of fossils, from genetic and anatomical studies, and from interpretation of the geological record. Most scientists agree that humans evolved from apelike primate ancestors in a process that began millions of years ago. Although all humans living today are members of a single subspecies, the fossil record confirms that our ancestors coexisted with a number of similar species throughout evolution.
Current theories trace the first hominid—upright walking, humanlike primate—to Africa, where sevearl distinct species appeared 5 – 7 million years ago. These species lieved in a variety of environments throughout the continent including swampy forests, woodlands, and open savanas. In addition to Australopithecus—best known from “Lucy, ” an Ethiopian specimen found in 1974—these early hominid species include such recent discoveries as Sehalanthropus, Andipithecus, Kenyanthropus, and Orrorin.
As I’ve been saying in some entry before about the crucial importance of quantification and math on getting real knowledge, the heart of the scientific method lies in that skeptic’s simple question. A merely plausible explanation of what we observe will not suffice, nor will a hypothesis bolstered only by some expert’s endorsement. Modern science is wonderfully egalitarian, and it demands proof that all can see: measurements, objects or evidence of some kind. Scientific hypotheses must be both well-defined and firmly supported, preferably by several different types of data.
And if a hypothesis meets these requirements, does this mean it is true? Certaintly no, according to the philosopher Karl Popper, who believed that hypotheses could never be proven true—only false (!). Frederick Nietzsche claimed as well that the great charm of hypotheses was that they were refutable. While Nietzsche may be correct in the abstract, my experience suggests that scientists do not gleefully bury hypotheses in which they have invested many years of research, or haven’t they?
As usual in the study of human evolution, vexing hypotheses are commonplace in the arena because of long-standing, frequently erupting feuds about the interpretation of the fossil record. The field is far argumentative, in part, because the theories reflect directly on the nature and origin of humans. There is immense room for giving and taking offense when the subject is oneself. Too, the primary data of paleoanthropology—fossilized remains of our ancestors and near-relatives—are rare and difficult to obtain. Hence, it is not a simple matter to collect more evidence to clarify or support hypotheses. Fossil hunting requires tremendous knowledge and effort, good organizational skills, substantial grants, and a huge dollop of luck. New theories are, sadly, easier to come by than new primary evidence.
Thenceforth it is a great occasion to present the issue of evolution; when, where and how modern humans evolved. For a minimalistical point of view, we can use or must use the terms, “modern humans” or “recent humans,” to denote such species to which everybody supposedly belongs, though the formal term is either “anatomically modern Homo sapiens” or “Homo sapiens sapiens.” Humans who lived in the past and did not have modern anatomy are often referred to as archaic or primitive. Nice remark!