What is Deep Time and Why Should Anyone Care?

The concept of deep time resulted directly from observations of nature and forms a cornerstone of the scientific description of nature. Field observations led early naturalists to such fruitful ideas as original horizontality, superposition, and spatial scales of events. These ideas in turn led to the notions of sequences, criteria for synchroneity, correlation, and to the recognition of systematic, temporal changes in life assemblages with their many implications for the evolution of life. Early naturalists realized that the earth has a multi-million year history; their inferences were vindicated eventually by the results of radiometric age determination. Being observation based, deep time is readily taught to students using local features, and its validity follows simply from the premise that natural phenomena contain real information. Appreciation of deep time helps us to define the limits to human consumption of Earth resources, as well as to provide a framework for debates among those who hold different views on the domains of validity for science and religion and on the meaning of scientific inferences.