Class 4: Isaac Newton

Readings

Articles to view or download: 

From the December 2019 issue of Astronomy "Isaac Newton: A vindictive, secretive, paranoid genius"; to view or download pdf, click here .

The articles below are excerpts from Newton's own writings (The Principia in translation), and may be a little difficult to read because of the context and the language. Rather than worrying about understanding them in detail, please just seek to get the sense of what he's saying. 

• Principia Book 1: Definitions (2+ pages); to view or download pdf, click here .

• Principia Book 1: Laws (1+ pages); to view or download pdf, click here .

• Principia Book 1: Scholium - on Time, Space and Motion (5 pages); to view or download pdf, click here .

• Principia Book III: Excerpts (6 pages); to view or download pdf, click here .

"The System of the World", "Rules of Reasoning in Philosophy", General Scholium".  

• Newton: "A short Scheme of the True Religion" (1 page); to view or download pdf, click here .

Points to Ponder

• An astronaut has a mass (quantity of matter) of 70 kilograms and weighs 686 newtons (yes, those are the metric units now) here on earth. If he travels to a planet with half the gravity of earth, what is his mass and how much does he weigh?  Out in space, what is his mass and how much does he weigh?

• You're an astronaut with the task of measuring gravity on a distant planetary moon. What sort of scale should you take for your measurement, a balance scale or a spring-loaded (bathroom-type) scale? Why?

• Could Newton's "A short Scheme of the True Religion" have been written in today's times? Please explain. What role does God play in Newton's universe? Is it different from Galileo's view?

• In summary, how do you think Newton changed the world view? 

Optional Reading and Viewing

For other reading and viewing, click on the link  Of Further Interest - Newton 

Updated Oct. 17. 2026