You have chosen 'The Decline of the West' by Oswald Spengler, 'An Axiomatization of Set Theory' by John von Neumann and 'On the Happy Life' by Seneca the Younger
start again | choose another area for these texts | all the ideas for this combination of texts| All the ideas for Natural Theory, or select a subheading: |
| A. | Speculations on Nature | |
| B. | Natural Kinds | |
| C. | Causation | |
| D. | Laws of Nature |