5 ideas
| 18758 | Validity is provable, but invalidity isn't, because the model is infinite [Church, by McGee] |
| Full Idea: Church showed that logic has a proof procedure, but no decision procedure. If an argument is invalid, there is a model with true premises and false conclusion, but the model will typically be infinite, so there is no way to display it concretely. | |
| From: report of Alonzo Church (A Note on the entscheidungsproblem [1936]) by Vann McGee - Logical Consequence 5 |
| 20653 | Six reduction levels: groups, lives, cells, molecules, atoms, particles [Putnam/Oppenheim, by Watson] |
| Full Idea: There are six 'reductive levels' in science: social groups, (multicellular) living things, cells, molecules, atoms, and elementary particles. | |
| From: report of H.Putnam/P.Oppenheim (Unity of Science as a Working Hypothesis [1958]) by Peter Watson - Convergence 10 'Intro' | |
| A reaction: I have the impression that fields are seen as more fundamental that elementary particles. What is the status of the 'laws' that are supposed to govern these things? What is the status of space and time within this picture? |
| 7598 | Zoroaster and the Hebrew prophets evolved different versions of monotheism [Zoroaster, by Armstrong,K] |
| Full Idea: Zoroaster and the Hebrew prophets evolved different versions of monotheism. | |
| From: report of Zoroaster (The Gathas (seventeen hymns) [c.900 BCE]) by Karen Armstrong - A History of God Ch.1 | |
| A reaction: This seems to be the consensus on the origins of monotheism, which places the development much earlier than the appearance of the idea in Greek philosophy. |
| 7472 | Zarathustra was the first to present a god who is an abstract concept [Zoroaster] |
| Full Idea: Zarathustra's achievement was for the first time to present a god who is an abstract concept - he broke with the tradition of a pantheon of gods. | |
| From: Zoroaster (The Gathas (seventeen hymns) [c.900 BCE]), quoted by Peter Watson - Ideas Ch.05 | |
| A reaction: The more abstract the gods become, the harder it is to challenge their existence. |
| 20672 | Zoroastrianism saw the world as a battle between good evil gods [Zoroaster, by Harari] |
| Full Idea: Zoroastrianism saw the world as a cosmic battle between the good god Ahura Mazda and the evil god Angra Mainyu. | |
| From: report of Zoroaster (The Gathas (seventeen hymns) [c.900 BCE]) by Yuval Noah Harari - Sapiens: brief history of humankind 12 'Battle' | |
| A reaction: Hm. This contradicts the impression I had gained that it was monotheist. |