15 ideas
| 17884 | Mathematical set theory has many plausible stopping points, such as finitism, and predicativism [Koellner] |
| Full Idea: There are many coherent stopping points in the hierarchy of increasingly strong mathematical systems, starting with strict finitism, and moving up through predicativism to the higher reaches of set theory. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], Intro) |
| 17893 | 'Reflection principles' say the whole truth about sets can't be captured [Koellner] |
| Full Idea: Roughly speaking, 'reflection principles' assert that anything true in V [the set hierarchy] falls short of characterising V in that it is true within some earlier level. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 2.1) |
| 17894 | We have no argument to show a statement is absolutely undecidable [Koellner] |
| Full Idea: There is at present no solid argument to the effect that a given statement is absolutely undecidable. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 5.3) |
| 17890 | There are at least eleven types of large cardinal, of increasing logical strength [Koellner] |
| Full Idea: Some of the standard large cardinals (in order of increasing (logical) strength) are: inaccessible, Mahlo, weakly compact, indescribable, Erdös, measurable, strong, Wodin, supercompact, huge etc. (...and ineffable). | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4) | |
| A reaction: [I don't understand how cardinals can have 'logical strength', but I pass it on anyway] |
| 17887 | PA is consistent as far as we can accept, and we expand axioms to overcome limitations [Koellner] |
| Full Idea: To the extent that we are justified in accepting Peano Arithmetic we are justified in accepting its consistency, and so we know how to expand the axiom system so as to overcome the limitation [of Gödel's Second Theorem]. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.1) | |
| A reaction: Each expansion brings a limitation, but then you can expand again. |
| 17891 | Arithmetical undecidability is always settled at the next stage up [Koellner] |
| Full Idea: The arithmetical instances of undecidability that arise at one stage of the hierarchy are settled at the next. | |
| From: Peter Koellner (On the Question of Absolute Undecidability [2006], 1.4) |
| 12270 | Being is one [Melissus, by Aristotle] |
| Full Idea: Being is one. | |
| From: report of Melissus (fragments/reports [c.443 BCE]) by Aristotle - Topics 104b23 | |
| A reaction: I can only really understand this in terms of physics, as the belief that ultimately there is one simple theory which explains everything. That project doesn't look terribly promising, despite the lovely simplifications of modern physics. |
| 19743 | A notebook counts as memory, if is available to consciousness and guides our actions [Clark/Chalmers] |
| Full Idea: Beliefs are partly constituted by features of the environment. ....a notebook plays for one person the same role that memory plays for another. ...The information is reliably there, available to consciousness, and to guide action, just as belief is. | |
| From: A Clark / D Chalmers (The Extended Mind [1998], §4) | |
| A reaction: This is the modern externalist approach to beliefs (along with broad content and external cognition systems). Not quite what we used to mean by beliefs, but we'll get used to it. I believe Plato wrote what it said in his books. Is memory just a role? |
| 6176 | A mechanism can count as 'cognitive' whether it is in the brain or outside it [Clark/Chalmers, by Rowlands] |
| Full Idea: If the operation of a brain implant inside the brain is a cognitive operation, why should it not count as a cognitive operation when it is outside the brain? There are many mechanisms which would count as cognitive if they were inside the subject. | |
| From: report of A Clark / D Chalmers (The Extended Mind [1998]) by Mark Rowlands - Externalism Ch.9 | |
| A reaction: This argues for externalism of the vehicle of thought, rather than its content. The idea is that there is no significant difference between remembering a phone number and writing it on a bit of paper. I find it hard to disagree. |
| 19741 | If something in the world could equally have been a mental process, it is part of our cognition [Clark/Chalmers] |
| Full Idea: If, as we confront some task, a part of the world functions as a process which, were it done in the head, we would have no hesitation in recognising as part of the cognitive process, then that part of the world is part of the cognitive process. | |
| From: A Clark / D Chalmers (The Extended Mind [1998], §2) | |
| A reaction: In some sense they are obviously right that our cognitive activities spill out into books, calculators, record-keeping. It seems more like an invitation to shift the meaning of the word 'mind', than a proof that we have got it wrong. |
| 19742 | Consciousness may not extend beyond the head, but cognition need not be conscious [Clark/Chalmers] |
| Full Idea: Many identify the cognitive with the conscious, and it seems far from plausible that consciousness extends outside the head in these cases. But not every cognitive process, at least on standard usage, is a conscious process. | |
| From: A Clark / D Chalmers (The Extended Mind [1998], §3) | |
| A reaction: This gives you two sorts of externalism about mind to consider. No, three, if you say there is extended conceptual content, then extended cognition processes, then extended consciousness. Depends what you mean by 'consciousness'. |
| 19744 | If a person relies on their notes, those notes are parted of the extended system which is the person [Clark/Chalmers] |
| Full Idea: If Otto relies on his notebook, what this comes to is that Otto himself is best regarded as an extended system, a coupling of biological organism and external resources. | |
| From: A Clark / D Chalmers (The Extended Mind [1998], §5) | |
| A reaction: You start to get giddy as you read this stuff. If two people constantly share a notebook, they begin to blend into one another. It inclines me towards a more 'animalist' view of the nature of a person or a self. |
| 3059 | There is no real motion, only the appearance of it [Melissus, by Diog. Laertius] |
| Full Idea: There is no such thing as real motion, but there only appears to be such. | |
| From: report of Melissus (fragments/reports [c.443 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.4.3 |
| 5100 | The void is not required for change, because a plenum can alter in quality [Aristotle on Melissus] |
| Full Idea: There is no need for void to be the cause of all change, because it is perfectly possible for a plenum to alter qualitatively (which is something Melissus overlooked). | |
| From: comment on Melissus (fragments/reports [c.443 BCE]) by Aristotle - Physics 214a27 | |
| A reaction: In modern physics this presumably gives us fluctuations in a force field. Motion is like a cat being digested by a python. The atomist claim that emptiness is needed if anything is to move still has intuitive appeal. |
| 456 | Nothing could come out of nothing [Melissus] |
| Full Idea: If Nothing existed, in no way could anything come into being out of nothing. | |
| From: Melissus (fragments/reports [c.443 BCE], B1), quoted by (who?) - where? |