1. Hutton’s Solution and “Deep Time” “ No vestige of a beginning… No prospect of an end.”

2. The Age of Enlightenment Late 18 th century Tremendous advances in science, politics, philosophy, economics, etc. Thomas Jefferson and Benjamin Franklin American figures in the Enlightenment

3. James Hutton A “gentleman farmer” Associate of James Watt and other members of the “Oyster Club” The Scottish Enlightenment – centered in Edinburgh (Edinboro)

4. Hutton and Deism Hutton was a Deist Deism held that one could gain greater understanding of God by understanding nature – his creation The “Denudation Dilemma - a theological conundrum

5. Denudation Dilemma Rock and soil are essential to life Rock is the foundation for where we live Soil is the foundation of agriculture – sustains life To the Deists, this was evidence of God’s beneficence

6. Denudation Dilemma Rocks decay at Earth’s surface – weathering Soil is washed away from farmlands – erosion Weathering and erosion indicate destruction of the land Martin Luther predicted that the world would end as a result of erosion

7. The Dilemma How can one reconcile God’s beneficence with the destruction of the land, which is essential for life?

8. Hutton’s Observations Processes of weathering and erosion are slow Many rocks visible on the land are made up of the products of weathering and erosion These rocks are Sedimentary Rocks Sediments accumulate in the ocean, so these rocks originally formed in the ocean

9. The Riddle How can rocks that formed below sea level be found on land?

10. More of Hutton’s Observations Not all rocks form by accumulation of sediment Some rocks are made of crystals These rocks show signs of having formed at very high temperatures from molten material These are Igneous Rocks

11. Arthur’s Seat and Salisbury Crags

12. Hutton’s Solution Igneous rocks provide evidence for heat within the Earth Heat is capable of work (Watt’s influence) Heat within the Earth lifts rocks from the sea and creates new land The dilemma is solved because as erosion destroys land, heat uplifts new land Concept of the Rock Cycle

13. Implications of Hutton’s Solution Earth processes are slow Great changes can be accomplished with great amounts of time Evidence of great expanses of time recorded by the rocks Conclusion: the Earth must be extremely old

14. Evidence for Deep Time – Hutton’s Unconformity

15. An old Earth Recycling of Earth materials Evidence for earlier episodes of recycling “No vestige of a beginning… no prospect of an end.” Hutton’s “Theory of the Earth” - 1785

16. Playfair’s Commentary “The mind seemed to grow giddy looking so far into the abyss of time…”

17. What’s so remarkable about Hutton’s Ideas? Contrary to prevailing views of the time Based on observation – what he saw Hutton drew inferences from his observations Inferences are hypotheses Hypotheses are testable This is an application of the scientific method to study of the Earth

18. Science and the Scientific Method Science – a way of knowing Objective Based on observation Scientific Method – a rational way of verifying what is “known” Nothing is absolutely “true” in science. All ideas are subject to rejection as they are tested

19. Science and the Scientific Method Proposed explanations are hypotheses Hypotheses are tested by Experimentation Prediction and verification Further observation Well-tested hypotheses may be elevated to the status of theory Well-tested theories may eventually become natural laws or simply laws