Paradoxes od vaccum from ancient metaphysics to present day physics Peter Zamarovský ČVUT, FEL, Technická 2, Praha 6 “I love talking about nothing. It is the only thing I know anything about.” G.B. Shaw

Definition of the concept of vacuum Socrates – exact definition of concepts Neologisms → hypostasis give rise of FORMS (Plato) Delineation (A. W. Watts) Leitmotif of analytical philosophy – improvement of language → epistemology → ontology → knowledge (science)

Problems with the concept of vacuum Concept of vacuum (KENON) – not clear (AITHER, AER …) Empedocles: aer is of material nature (KLEPSHYDRA) AER filling of Cosmos ? Archytas of Tarentum – music of spheres(?), Kepler (17 th cent.) – Somnium (Moonflight dream) – aer on Moon Vacuum – absence of palpable (solid ?) matter Logical proof of nonexistence of vacuum Parmenides – PERI FYSEÓS (On Nature) (difficult metaphysical poem ) - paradox of negative existentials No-beingness is neither perceptible nor knowable But: “to be conceived” and “to be” is the same (there is only one criterion of being – our thinking, conceiving (NOEIN)) From this: No-beingness (ME ON) does not exist! Cyclops Polyphemos Odysseus: I am Nobody: No provident to use negative concepts!

Problems with the concept of vacuum Melissos of Samos – jump to physical level “Nor is anything empty, because to be empty means to be nothing and to be nothing means not to be.” “Vacuum” (KENON) – contradictory concept (pseudoconcept) – does not correspond to anything Later (Aristotle): + physical argument HORROR VACUI

Problems with the concept of vacuum Descartes ( ): corpuscular space „If a vessel would be completely empty, its walls would be in mutual contact, as nothing would be among them.“ Thomas Hobbes ( ): Boyle (Robert Boyle ) supposition that gas consists of particles moving in free space (kinetic theory of gases) can not be correct – there is no free space! Newton ( ) Absolute (free) space - SENSORIUM DEI (accelerated, rotational motion with respect to the “absolute space”)

Another way: vacuum exists Leucippus Universe consists from fullness and emptiness. The Emptiness is no less then the fullness. Aristotle... Those who try to show that there is no free space … do not understand it … they suppose that everything that exist must be bodily. Physics IV, 214a, 17-30

Vacuum However: Inertia testify against existence of emptiness. Aristotle, Physics VIII. Epicureans and Stoics: It is therefore the space is empty and nonpalpable. Otherwise, in no way things could move. Lucretius Carus (cca 50 BC), De Rerum Natura

Period of classical physics J. E. Torriceli, Perrier, Otto von Guericke, “technical vacuum”

Period of modern (classical) physics End of SENSORIUM DEI Inertial system (Lang- circular definition) E. Mach: Mach principle (Einstein): “Inertial forces” have to be caused by mass of the Universe, no by “empty space” (Close masses evidently do not play any role.) A. Einstein – OTR Tensor of gravitational field

Optics Light wave nature (Young experiments, interference) What is undulating? Ether. Ether is 1.Fulfill the space 2.Creates the space

Ether fulfill the space Simon Newcomb (1878) John Gore (1888) Bubbles (drops) of ether (dark sky paradox) But: Polarization of light → Transversal waves! Problems with modeling ether Experiments of Michelson and Morley (1881, 1887) → constant speed of light, end of ether

Current status Substantial understanding, vacuum is not emptiness but fullness, even fundamental fullness “school physics”, Newtonian approximation, mechanics: vacuum = empty space (how much “empty?”) Deeper approximation of present physics: OTR – tensor field QED – sea of virtual particles

Some new aspects: Return of the absolute space (?) Commoving system Relict radiation (Cosmic background radiation) Hidden energy of vacuum – QED Discovery of accelerated expansion of universe (1998) „dark energy“ There is no unifying view.