124 ideas
18889 | Ostensive definitions needn't involve pointing, but must refer to something specific [Salmon,N] |
14684 | A world is 'accessible' to another iff the first is possible according to the second [Salmon,N] |
14669 | For metaphysics, T may be the only correct system of modal logic [Salmon,N] |
14667 | System B has not been justified as fallacy-free for reasoning on what might have been [Salmon,N] |
14668 | In B it seems logically possible to have both p true and p is necessarily possibly false [Salmon,N] |
14692 | System B implies that possibly-being-realized is an essential property of the world [Salmon,N] |
14671 | What is necessary is not always necessarily necessary, so S4 is fallacious [Salmon,N] |
14627 | S4, and therefore S5, are invalid for metaphysical modality [Salmon,N, by Williamson] |
14686 | S5 modal logic ignores accessibility altogether [Salmon,N] |
14691 | S5 believers say that-things-might-have-been-that-way is essential to ways things might have been [Salmon,N] |
14693 | The unsatisfactory counterpart-theory allows the retention of S5 [Salmon,N] |
14670 | Metaphysical (alethic) modal logic concerns simple necessity and possibility (not physical, epistemic..) [Salmon,N] |
458 | Nothing could come out of nothing, and existence could never completely cease [Empedocles] |
19482 | Current physics says matter and antimatter should have reduced to light at the big bang [New Sci.] |
19483 | CP violation shows a decay imbalance in matter and antimatter, leading to matter's dominance [New Sci.] |
5112 | Empedocles says things are at rest, unless love unites them, or hatred splits them [Empedocles, by Aristotle] |
14742 | It can't be indeterminate whether x and y are identical; if x,y is indeterminate, then it isn't x,x [Salmon,N] |
13209 | There is no coming-to-be of anything, but only mixing and separating [Empedocles, by Aristotle] |
18888 | Essentialism says some properties must be possessed, if a thing is to exist [Salmon,N] |
14678 | Any property is attached to anything in some possible world, so I am a radical anti-essentialist [Salmon,N] |
457 | Substance is not created or destroyed in mortals, but there is only mixing and exchange [Empedocles] |
14680 | Logical possibility contains metaphysical possibility, which contains nomological possibility [Salmon,N] |
14690 | In the S5 account, nested modalities may be unseen, but they are still there [Salmon,N] |
14677 | Metaphysical necessity is said to be unrestricted necessity, true in every world whatsoever [Salmon,N] |
14679 | Bizarre identities are logically but not metaphysically possible, so metaphysical modality is restricted [Salmon,N] |
14688 | Without impossible worlds, the unrestricted modality that is metaphysical has S5 logic [Salmon,N] |
14685 | Metaphysical necessity is NOT truth in all (unrestricted) worlds; necessity comes first, and is restricted [Salmon,N] |
14681 | Logical necessity is free of constraints, and may accommodate all of S5 logic [Salmon,N] |
14676 | Nomological necessity is expressed with intransitive relations in modal semantics [Salmon,N] |
14689 | Necessity and possibility are not just necessity and possibility according to the actual world [Salmon,N] |
14674 | Impossible worlds are also ways for things to be [Salmon,N] |
14682 | Denial of impossible worlds involves two different confusions [Salmon,N] |
14687 | Without impossible worlds, how things might have been is the only way for things to be [Salmon,N] |
14683 | Possible worlds rely on what might have been, so they can' be used to define or analyse modality [Salmon,N] |
14672 | Possible worlds are maximal abstract ways that things might have been [Salmon,N] |
14675 | Possible worlds just have to be 'maximal', but they don't have to be consistent [Salmon,N] |
14673 | You can't define worlds as sets of propositions, and then define propositions using worlds [Salmon,N] |
462 | One vision is produced by both eyes [Empedocles] |
19737 | A system can infer the structure of the world by making predictions about it [New Sci.] |
19736 | Neural networks can extract the car-ness of a car, or the chair-ness of a chair [New Sci.] |
22765 | Wisdom and thought are shared by all things [Empedocles] |
1524 | For Empedocles thinking is almost identical to perception [Empedocles, by Theophrastus] |
16419 | No one has yet devised a rationality test [New Sci.] |
16417 | About a third of variation in human intelligence is environmental [New Sci.] |
16418 | People can be highly intelligent, yet very stupid [New Sci.] |
19484 | Psychologists measure personality along five dimensions [New Sci.] |
18886 | Frege's 'sense' solves four tricky puzzles [Salmon,N] |
18887 | The perfect case of direct reference is a variable which has been assigned a value [Salmon,N] |
18885 | Kripke and Putnam made false claims that direct reference implies essentialism [Salmon,N] |
552 | Empedocles said good and evil were the basic principles [Empedocles, by Aristotle] |
589 | 'Nature' is just a word invented by people [Empedocles] |
21823 | The principle of 'Friendship' in Empedocles is the One, and is bodiless [Empedocles, by Plotinus] |
2680 | Empedocles said that there are four material elements, and two further creative elements [Empedocles, by Aristotle] |
6002 | Empedocles says bone is water, fire and earth in ratio 2:4:2 [Empedocles, by Inwood] |
13207 | Fire, Water, Air and Earth are elements, being simple as well as homoeomerous [Empedocles, by Aristotle] |
459 | All change is unity through love or division through hate [Empedocles] |
13218 | The elements combine in coming-to-be, but how do the elements themselves come-to-be? [Aristotle on Empedocles] |
13225 | Love and Strife only explain movement if their effects are distinctive [Aristotle on Empedocles] |
460 | If the one Being ever diminishes it would no longer exist, and what could ever increase it? [Empedocles] |
18891 | Nothing in the direct theory of reference blocks anti-essentialism; water structure might have been different [Salmon,N] |
21167 | Gravity is unusual, in that it always attracts and never repels [New Sci.] |
19950 | Entropy is the only time-asymmetric law, so time may be linked to entropy [New Sci.] |
21176 | In the Big Bang general relativity fails, because gravity is too powerful [New Sci.] |
21147 | Quantum electrodynamics incorporates special relativity and quantum mechanics [New Sci.] |
21155 | Photons have zero rest mass, so virtual photons have infinite range [New Sci.] |
19478 | Light moves at a constant space-time speed, but its direction is in neither space nor time [New Sci.] |
21161 | In the standard model all the fundamental force fields merge at extremely high energies [New Sci.] |
21146 | Electrons move fast, so are subject to special relativity [New Sci.] |
19474 | Quantum states are measured by external time, of unknown origin [New Sci.] |
19473 | The Schrödinger equation describes the evolution of an object's wave function in Hilbert space [New Sci.] |
21148 | The strong force is repulsive at short distances, strong at medium, and fades at long [New Sci.] |
21151 | Gluons, the particles carrying the strong force, interact because of their colour charge [New Sci.] |
21152 | The strong force binds quarks tight, and the nucleus more weakly [New Sci.] |
21142 | Classifying hadrons revealed two symmetry patterns, produced by three basic elements [New Sci.] |
21143 | Quarks in threes can build hadrons with spin ½ or with spin 3/2 [New Sci.] |
21150 | Three different colours of quark (as in the proton) can cancel out to give no colour [New Sci.] |
21145 | The four fundamental forces (gravity, electromagnetism, weak and strong) are the effects of particles [New Sci.] |
21153 | The weak force explains beta decay, and the change of type by quarks and leptons [New Sci.] |
21154 | Three particles enable the weak force: W+ and W- are charged, and Z° is not [New Sci.] |
21156 | The weak force particles are heavy, so the force has a short range [New Sci.] |
21164 | Why do the charges of the very different proton and electron perfectly match up? [New Sci.] |
21170 | The Standard Model cannot explain dark energy, survival of matter, gravity, or force strength [New Sci.] |
21140 | Spin is a built-in ration of angular momentum [New Sci.] |
21149 | Quarks have red, green or blue colour charge (akin to electric charge) [New Sci.] |
21158 | Fermions, with spin ½, are antisocial, and cannot share quantum states [New Sci.] |
21165 | Spin is akin to rotation, and is easily measured in a magnetic field [New Sci.] |
21157 | Particles are spread out, with wave-like properties, and higher energy shortens the wavelength [New Sci.] |
21163 | The mass of protons and neutrinos is mostly binding energy, not the quarks [New Sci.] |
21168 | Gravitional mass turns out to be the same as inertial mass [New Sci.] |
21138 | Neutrons are slightly heavier than protons, and decay into them by emitting an electron [New Sci.] |
21144 | Top, bottom, charm and strange quarks quickly decay into up and down [New Sci.] |
21141 | Neutrinos were proposed as the missing energy in neutron beta decay [New Sci.] |
21169 | Only neutrinos spin anticlockwise [New Sci.] |
21166 | Standard antineutrinos have opposite spin and opposite lepton number [New Sci.] |
21171 | The symmetry of unified electromagnetic and weak forces was broken by the Higgs field [New Sci.] |
19954 | It is impossible for find a model of actuality among the innumerable models in string theory [New Sci.] |
21178 | String theory is now part of 11-dimensional M-Theory, involving p-branes [New Sci.] |
21175 | String theory might be tested by colliding strings to make bigger 'stringballs' [New Sci.] |
21177 | String theory offers a quantum theory of gravity, by describing the graviton [New Sci.] |
19953 | In string theory space-time has a grainy indivisible substructure [New Sci.] |
19476 | String theory needs at least 10 space-time dimensions [New Sci.] |
21179 | Supersymmetric string theory can be expressed using loop quantum gravity [New Sci.] |
21159 | Supersymmetry has extra heavy bosons and heavy fermions [New Sci.] |
21162 | Only supersymmetry offers to incorporate gravity into the scheme [New Sci.] |
21173 | Supersymmetry says particles and superpartners were unities, but then split [New Sci.] |
21172 | The evidence for supersymmetry keeps failing to appear [New Sci.] |
19947 | Hilbert Space is an abstraction representing all possible states of a quantum system [New Sci.] |
21160 | The Higgs field means even low energy space is not empty [New Sci.] |
19948 | Einstein's merging of time with space has left us confused about the nature of time [New Sci.] |
19475 | Relativity makes time and space jointly basic; quantum theory splits them, and prioritises time [New Sci.] |
19955 | Space-time may be a geometrical manifestation of quantum entanglement [New Sci.] |
19949 | Quantum theory relies on a clock outside the system - but where is it located? [New Sci.] |
19951 | Entropy is puzzling, so we may need to build new laws which include time directionality [New Sci.] |
19477 | General relativity predicts black holes, as former massive stars, and as galaxy centres [New Sci.] |
19952 | Black holes have entropy, but general relativity says they are unstructured, and lack entropy [New Sci.] |
16420 | 84.5 percent of the universe is made of dark matter [New Sci.] |
21174 | Dark matter must have mass, to produce gravity, and no electric charge, to not reflect light [New Sci.] |
17604 | We are halfway to synthesising any molecule we want [New Sci.] |
17603 | Chemistry just needs the periodic table, and protons, electrons and neutrinos [New Sci.] |
5090 | Maybe bodies are designed by accident, and the creatures that don't work are destroyed [Empedocles, by Aristotle] |
466 | God is pure mind permeating the universe [Empedocles] |
461 | God is a pure, solitary, and eternal sphere [Empedocles] |
1719 | In Empedocles' theory God is ignorant because, unlike humans, he doesn't know one of the elements (strife) [Aristotle on Empedocles] |
1522 | It is wretched not to want to think clearly about the gods [Empedocles] |