| ¬E → ¬D | If I do not exist, then I cannot do anything. | ||
| P → D | If I perceive thoughts, then I am doing something. | ||
| P | I perceive thoughts. | ||
| ∴ | T → E | If I think, therefore I am (Cogito, ergo sum). |
... which we can make into a truth tree.
| ¬(T → E) | Negation of Conclusion. |
| ↓ | |
| T ∧ ¬E | Logical Transformation |
| ↓ | |
| T | |
| ↓ | "AND" Statement |
| ¬E | |
| ↓ | |
| ¬E → ¬D | Premise 1 |
| ↙ ↘ | |
| E ¬D | "If-Then" Statement |
| X ↓ | |
| P → D | Premise 2 |
| ↙ ↘ | |
| ¬P D | "If-Then" Statement |
| ↓ X | |
| P | |
| X |
All Branches Are Closed!
The Argument is Valid!