# logic

What are mathematical proofs, why do we need them and what can they say about sheep? |
On the face of it the Universe is a fairly complex place. But could mathematics ultimately lead to a simple description of it? In fact, should simplicity be a defining feature of a "theory of everything"? We ponder the answers. |

Paraconsistent mathematics is a type of mathematics in which contradictions may be true.
In such a system it is perfectly possible for a statement
A and its negation not A to both be true. How can this be, and be coherent? What does it all mean? |
We all take for granted that mathematics can be used to describe the world, but when you think about it this fact is rather stunning. This article explores what the applicability of maths says about the various branches of mathematical philosophy. |

Almost nothing tangible remains of the legendary Bletchley Park codebreaker Alan Turing. So when an extremely rare collection of papers relating to his life and work was set to go to auction last year, an ambitious campaign was launched to raise funds to purchase them for the Bletchley Park Trust and its Museum. The Trust has announced today that the collection has been saved for the nation as the National Heritage Memorial Fund (NHMF) has stepped in quickly to provide £213,437, the final piece of funding required. |
In the 1930s the logician Kurt Gödel showed that if you set out proper rules for mathematics, you lose the ability to decide whether certain statements are true or false. This is rather shocking and you may wonder why Gödel's result hasn't wiped out mathematics once and for all. The answer is that, initially at least, the unprovable statements logicians came up with were quite contrived. But are they about to enter mainstream mathematics? |

It requires only a little processing power, but it's a giant leap for robotkind: engineers at the University of Southampton have developed a way of equipping spacecraft and satellites with human-like reasoning capabilities, which will enable them to make important decisions for themselves. |
Many people like mathematics because it gives definite answers. Things are either true or false, and true things seem true in a very fundamental way. But it's not quite like that. You can actually build different versions of maths in which statements are true or false depending on your preference. So is maths just a game in which we choose the rules to suit our purpose? Or is there a "correct" set of rules to use? We find out with the mathematician Hugh Woodin. |

If you like mathematics because things are either true or false, then you'll be worried to hear that in some quarters this basic concept is hotly disputed. In this article
Phil Wilson looks at constructivist mathematics, which holds that some things are neither true, nor false, nor anything in between. |
What's the nature of infinity? Are all infinities the same? And what happens if you've got infinitely many infinities? In this article
Richard Elwes explores how these questions brought triumph to one man and ruin to another, ventures to the limits of mathematics and finds that, with infinity, you're spoilt for choice. |