Physical anthropologists derive knowledge through the scientific method.Physical anthropologists carefully and systematically observe the natural world around them. These observations form the basis for identifying problems, developing questions, and gathering evidence data that will help answer the questions and solve the problems, fill gaps in scientific knowledge about how the natural world operates. These data are used to test hypotheses, possible explanations for the processes under study. Scientists observe and then reject or accept these hypotheses. This process of determining whether ideas are right or wrong is called the scientific method. It is the foundation of science.
Science is more than just knowledge of the facts about the natural world. Science is a way of acquiring knowledge—a way of knowing—through observation of natural phenomena. This repeated acquisition results in an ever-expanding knowledge base. In this way, science is empirical, or based on observation or experience. After the systematic collection of observations, the scientist develops a theory—an explanation, not just a description, of phenomena. A theory is an explanation grounded in a great deal of evidence.A scientist builds a case by identifying incontrovertible facts. To arrive at these facts, the scientist examines and reexamines the evidence, putting it through many tests.
The scientist thus employs observation, documentation, and testing to generate hypotheses and, eventually, to construct a theory based on those hypotheses. Hypotheses explain observations, predict the results of future investigation, and can be refuted by new evidence.
Scientists use these hypotheses to build theories. Theories can be modified or even replaced by better theories, depending on findings made through meticulous observation. As observations and hypotheses and theories are tested and subjected to the test of time, science revises its own errors.
If a theory proves absolutely true, it becomes a scientific law. Among the few scientific laws, the well-known ones are the laws of gravity, thermodynamics, and motion. But scientific truth seldom gets finalized into law. Rather, truth is continuousy developed,new facts are discovered and new understandings about natural phenomena are made.
Source-Larsen Essentials of Physical Anthropology by Clark Spencer Larsen