Home > Roger Penrose

In 1967, Penrose invented twistor theory which maps geometric objects in Minkowski space into the 4-dimensional complex space with the metric signature (2,2). In 1969 he conjectured the cosmic censorship hypothesis. This proposes (rather informally) that the universe protects us from the inherent unpredictability of singularities (such as black holes) by hiding them from our view.

Roger Penrose is well-known for his 19741974 is a common year starting on Tuesday (click on link for calendar). Events January-February January 5 Dungeons & Dragons officially released. February 4 Patricia Hearst, the 19 year old granddaughter of publisher William Randolph Hearst, is kidnapped discovery of Penrose tilingA Penrose tiling is pattern of tiles, discovered by Roger Penrose, which could completely cover an infinite surface, but only in a pattern which is non-repeating (aperiodic). Some Penrose tilings There are several different sets of Penrose tiles; the imags, which are formed from two tiles that can only tileIn geometry, a tiling (also called tessellation mosaic or dissection of a given shape S consists of a collection of other shapes which precisely cover S. Often the shape S to be tiled is the Euclidean plane, but other shapes and three-dimensional objects the plane aperiodically. In 1984This page is about the year 1984. For other uses of 1984, see 1984 (disambiguation). 1984 is a leap year starting on Sunday (link shows calendar). Events January January 1 Brunei becomes a fully independent state January 1 AT&T is broken up into 22 indepe, similar patterns were found in the arrangement of atoms in quasicrystalQuasicrystals are a peculiar form of solid in which the atoms of the solid are arranged in a seemingly regular, yet non-repeating structure. They were first observed by Dan Shechtman in 1982. Patterns in quasicrystals In a normal crystalline solid the poss. His most important contribution may be his 19711971 is a common year starting on Friday (click for link to calendar). Events January January 1 British divorce Reform Act comes into force January 2 66 die in stairway crush at Rangers v Celtic football match, Glasgow, Scotland. See Ibrox disaster. Janua invention of spin networkA spin network is a graph whose edges are associated with representations of a Lie group, G and vertices are associated with intertwiners of the edge reps adjacent to it. It was invented by Roger Penrose in 1971. Spin networks were applied to the physicss, which later came to form the geometry of spacetimeIn special relativity and general relativity, time and three-dimensional space are treated together as a single four-dimensional manifold called spacetime . A point in spacetime may be referred to as an event . Each event has four coordinates t x y z ; or in loop quantum gravity. He was influential in popularizing what are commonly known as Penrose diagrams (causal diagrams).

He has written books such as The Emperor's New Mind where he argues that known laws of physics do not constitute a complete system, and that true artificial intelligence is impossible. In this controversial book, he argues this based on claims that humans can do things outside the power of formal logic systems, such as knowing the truth of unprovable statements, or solving the halting problem. These claims were originally made by the philosopher John Lucas of Merton College, Oxford.

Later on, Penrose followed up The Emperor's New Mind with Shadows of the Mind and The Large, the Small and the Human Mind , further updating and explaining his theories.

Most mathematicians consider these claims to be mathematically incorrect. See the articles on Gödel's incompleteness theorem, the Church-Turing thesis and the halting problem for more on their reasoning.

According to Marvin Minsky, human beings can understand things to be true facts which are false, and therefore the process of understanding is not limited by mathematical systems of formal logic. Further, AI programs can also conclude that false statements are true, so this is not unique to humans.

Penrose and Stuart Hameroff have constructed a theory in which human consciousness is the result of quantum gravity effects in microtubules. This is widely considered a crank view in that it defies Occam's Razor. Max Tegmark, in a paper in Physical Review E, calculated that the time scale of neuron firing and excitations in microtubules is slower than the decoherence time by a factor of at least 10,000,000,000; this paper has been widely cited by critics of the Penrose-Hameroff proposal. However, this paper has since been claimed by Hameroff to be based on a number of incorrect assumptions. See the refutation linked below from Hameroff, Hagan and Tuczynksi . The general gist of the linked page is summed up by this statement in support of Tegmark : Physicists outside the fray, such as IBM's John Smolin , say the calculations confirm what they had suspected all along. "We're not working with a brain that's near absolute zero. It's reasonably unlikely that the brain evolved quantum behavior," he says. And another quote, this one from Charles Seife : Penrose, the Oxford mathematician famous for his work on tiling the plane with various shapes, is one of a handful of scientists who believe that the ephemeral nature of consciousness suggests a quantum process.

In 2004 Penrose released , a 1000 page book aimed at giving a comprehensive guide to the laws of physics.

Roger Penrose is the son of scientist Lionel S. Penrose, and the brother of mathematician Oliver Penrose and chess grandmaster Jonathan Penrose.