You have chosen 'On Duties ('De Officiis')' by M. Tullius Cicero, 'On the General Idea of Proof Theory' by Dag Prawitz and 'Set Theory' by Kenneth Kunen
start again | choose another area for these texts | all the ideas for this combination of texts| All the ideas for Existence, or select a subheading: |
| A. | Nature of Existence | |
| B. | Change in Existence | |
| C. | Structure of Existence | |
| D. | Theories of Reality | |
| E. | Categories |