Lecture 55_ The Newtonian Cosmos

Lecture Overview

Post-18th century, Newton has had unparalleled influence in science and numerous writings about him.
Famous quote: "Nearer the gods no mortal may approach."
Key question posed: What are the nature and limits of human knowing?
Newton's inventions and concepts form the foundation of modern physics, essential for today’s technology.
This era is known as the Scientific Revolution, shifting from medieval understanding of the physical world to a new paradigm.

Visionary in natural philosophy/science.
Machines as the key to power over nature, exemplified by inventions like the magnetic compass, gunpowder, and printing press.

Contributed to understanding that knowledge of self requires knowledge of the natural world.
Influenced Newton's early studies and views on nature and God.

Telescope: Enabled the discovery of a heliocentric universe, revolutionizing celestial understanding.
Microscope: Uncovered the hidden microscopic world, challenging previous conceptions of reality.
- Questions raised about the essence of light and seeing.
Ancient views: Light as a power, colors crucial for visual perception.

Revolutionized comprehension: The colors seen in a prism reflect those of the objects themselves (e.g., the 'red' of an apple).
Insight: Color not an inherent quality of objects, but a construct of optical perception and brain processing.
Heat is perceived energy, not an inherent property of objects.

Views on matter: Denied emptiness; sunlight viewed as pressure from matter.
Color perception in prisms explained through particle movement and energy dynamics.

Investigates limits of Cartesian color theory using prisms.
Key Questions:
- Are color perceptions merely events in our nervous systems?
- How do colors behave when passing through multiple prisms?
Findings show that colors remain unchanged after passing through a second prism, challenging Descartes’ theories.
Concluded that white light contains all colors, each with distinct mathematical properties that dictate bending in mediums like glass.

Why do we see red apples as red?
- Apples absorb other colors and reflect red light.
- Introduced concept of sunlight as a mixture of colors, revealing only part of the electromagnetic spectrum to the human eye.
Led to technological advancements (e.g., cell phones, microwaves, X-rays) by understanding energy balance emitted by the sun and our reflections.

Newton’s work expresses mathematical laws of attraction among celestial bodies.
Motion: Post-Galileo shift from Aristotle and Dante’s explanations focused on divine substance to physics and mechanics.
Contrasted Descartes' view on planetary motion:
- Descartes: Bodies move in straight lines unless acted upon.
- Newton: Formulated that planets follow mathematical laws (Kepler's elliptical orbits).
Newton’s stance against the view that the laws of motion lacked philosophical causes; he bore theological implications.

Universal Laws of Gravitation: All matter influenced by gravity.
Newton's belief in God as a skilled mechanic and geometer.
Asserted that mathematics and design in the universe indicate an infinitely wise cause.