The open web · A selected collection
Worth
exploring.
Good places to follow a question.
Spinoza and Euclid are starting points. Here are texts to return to, tools to think with, and a few beautiful detours into mathematics, philosophy, and science.
Browse 18 destinationsRead a source. Follow a proof.
Leave with a better question.
Three places to begin
Choose what catches your curiosity.
01 / Explore
Spinoza, at the source
Read the work, meet an interpretation, and keep the two in conversation.
Back to the directory ↑-
The Ethics
The full work, available to read online or download. Keep this beside the course when you want to see the definitions, proofs, and scholia in their original sequence.
Try this Read the appendix to Part I. Which explanations of human behaviour does Spinoza challenge?
gutenberg.org
-
Spinoza in more approachable English
The Ethics, political writings, and correspondence in versions designed to make the language easier to follow. These are editorial adaptations; compare important passages with another translation.
Try this Read the same proposition in Bennett and Elwes. Notice what becomes clearer—and what changes.
earlymoderntexts.com
-
A scholarly map of Spinoza
A substantial introduction to his life, metaphysics, mind, emotions, religion, and politics, with a bibliography for further reading. A useful companion when the system starts to feel too large.
Try this Pick one section after its matching course chapter. Write down one question the overview leaves open.
plato.stanford.edu
-
Power, religion, and political freedom
A closer look at Spinoza’s political arguments and their tensions. Useful for going beyond a slogan about freedom of thought and asking how his institutions and exclusions fit together.
Try this Compare the role of reason in an individual life with its role in the design of a state.
plato.stanford.edu
-
Listen to the Ethics
An audio reading of the work. Hearing the sequence can make familiar passages feel different; keep the written text nearby for proposition numbers and the steps of a proof.
Try this Listen to a short section, then explain its argument without looking at the page.
librivox.org
02 / Explore
Euclid, with a pencil
Move between the text, the picture, and a construction of your own.
Back to the directory ↑-
Byrne’s Euclid, in colour
A beautifully made digital recreation of Oliver Byrne’s 1847 edition of the first six books. Coloured shapes and interactive diagrams offer another way into a geometric argument.
Try this Open Book I and follow a single proposition. Translate the coloured relationships into sentences.
c82.net
-
All thirteen books of the Elements
A detailed reference for definitions, propositions, and their connections throughout the Elements. The text and commentary are the main attraction; some older applet features may not work in modern browsers.
Try this Find Book I, proposition 1. Identify which definitions and postulates the construction relies on.
mathcs.clarku.edu
-
A geometry workbench
Construct points, circles, and lines, then move them to explore relationships. Excellent for testing a conjecture before writing a proof; a convincing picture is still only a starting point.
Try this Construct a perpendicular bisector. Drag an endpoint and ask why the equal distances persist.
geogebra.org
-
Who was Euclid?
Historical context for Euclid and the Elements, including the limits of what we know about his life. A useful antidote to treating a familiar name as a complete biography.
Try this Separate a documented fact, a later report, and an uncertain claim in the account.
mathshistory.st-andrews.ac.uk
03 / Explore
Ideas you can play with
Build, watch, and experiment. Let curiosity supply the first question.
Back to the directory ↑-
Polypad
A canvas of polygons, tiles, number tools, and other mathematical objects. Use it to make patterns and test a construction with your hands before reaching for formal notation.
Try this Build the same shape from two different sets of tiles. Can you explain why their areas agree?
polypad.amplify.com
-
Mathematics made visible
Animated explanations of geometry, calculus, linear algebra, probability, and more. A rewarding next stop when you want the picture behind a formula, with topics to explore well beyond Euclid.
Try this Pause before an explanation resolves. Sketch your prediction, then compare it with the result.
3blue1brown.com
-
Seeing Theory
A visual introduction to probability and statistics, from chance events to Bayesian inference. The site is archived for reference, but its visual approach remains a useful way to investigate uncertainty.
Try this Start with basic probability. Describe the difference between one outcome and a long-run pattern.
seeing-theory.brown.edu
-
The Evolution of Trust
An interactive introduction to how cooperation can develop—or break down—in repeated games. It pairs naturally with questions about social life, while remaining a simplified model rather than a theory of every relationship.
Try this Change a condition in the game. Which behaviour succeeds now, and why did the result change?
ncase.me
04 / Explore
Follow the next question
A few wider doors into philosophy, logic, science, and the pleasure of understanding.
Back to the directory ↑-
The Stanford Encyclopedia of Philosophy
A scholar-written reference for exploring a philosophical problem in depth. Follow the bibliography and related entries when a question about causation, freedom, or knowledge leads beyond one thinker.
Try this Look up a concept you keep using. Find a distinction you had been overlooking.
plato.stanford.edu
-
The Internet Encyclopedia of Philosophy
An independent collection of philosophy articles written by professional philosophers. Reading a second account of the same subject can expose assumptions that disappear when you rely on a single guide.
Try this Compare two introductions to the same thinker. Where do their emphases differ?
iep.utm.edu
-
Learn to make an argument precise
A free introduction to formal logic, with truth tables, quantifiers, and natural deduction. Downloadable exercises and solutions let you carry the habit of proof into a different kind of reasoning.
Try this Begin with the distinction between a true conclusion and a valid argument.
forallx.openlogicproject.org
-
Quanta Magazine
Reporting on mathematics and fundamental science, with explanations that reward patient reading. A place to meet current questions after working through older systems of thought.
Try this Choose one article. Identify what is established, what is conjectured, and what remains unknown.
quantamagazine.org
-
Explorable Explanations
A collection of explanations you learn by interacting with. Wander across subjects and notice how a well-chosen simulation can turn an abstract relationship into a question you can investigate.
Try this Explore one model, then name a feature of the real world that it deliberately leaves out.
explorabl.es
A guided path, here on the site
Bring the discoveries back.
Work through the courses, then return to these sources with sharper questions.
Selected for relevance, clarity, and the pleasure of discovery. Descriptions reviewed . External resources are maintained by their respective creators. Suggest a resource or report a broken link →