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SYMPOSIUM & THEATRE PERFORMANCE
Turing100.nl
Friday, October 5, 2012, Amsterdam

VvL: De Nederlandse Vereniging voor Logica & Wijsbegeerte der Exacte Wetenschappen
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We are happy to invite you for the Symposium Turing100.nl to celebrate the centenary of Alan Turing 
(1912-1954). The day will be organized by the Nederlandse Vereniging voor Logica & Wijsbegeerte 
der Exacte Wetenschappen (VvL).

Symposium: 11.30-17.15, in the "Hella Haasse/Simon Vestdijk" room on the 6th floor of the OBA 
Theatre Performance 'Breaking the Code': 19.30-21.45 in the "Theater van 't Woord" on the 7th 
floor of the OBA Location: 
Openbare Bibliotheek Amsterdam, Centrale Bibliotheek, Oosterdokskade 143
(http://www.oba.nl)

http://www.turing100.nl/

The speakers of the Symposium are:

Antonina Kolokolova (St. John's, Canada)
Liesbeth De Mol          (Gent, Belgium)
Jan van Leeuwen        (Utrecht, The Netherlands)
Andrew Hodges   (Oxford, United Kingdom)
Bennie Mols      (Amsterdam, The Netherlands)

In addition, we will have the general meeting of the VvL members during lunch. Those members who 
participate in the general meeting will be offered a free lunch.

The event has been financially sponsored by NWO and IHLIA (Internationaal homo lesbisch 
informatiecentrum en archief).

Please find the full program and abstracts of the lectures below.

Kind regards,

Balder ten Cate
Benedikt Löwe
Vincent van Oostrom
Femke van Raamsdonk
Elias Thijsse
Rineke Verbrugge

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PROGRAM OF THE SYMPOSIUM & THEATRE PERFORMANCE TURING100.NL

11:00-11:30: Arrival and coffee

11:30-12:15 Antonina Kolokolova (St. Johns, Canada)
Title: How hard is proving hardness? Logic approach to barriers in complexity

Abstract: In spite of much work over the years, the main questions in complexity theory such as 
P vs. NP remain unresolved.  Is this question solvable at all? Is P vs. NP independent of some 
logical theory?  Indeed, on a meta-level, there are several results that state that certain 
classes of techniques, including Turing's celebrated diagonalization, cannot be used to resolve 
these questions. Such results we call the "barriers" of complexity theory. In this talk, we will 
survey some of the main such barriers (Relativization, Natural Proofs, Algebrization), and talk 
about how knowledge of such barriers helps evaluate (and, so far, discard) proposed proofs of P 
vs. NP.  We will talk about the logic basis for such barriers, where a barrier means an 
independence of a logic theory.

12:15-13:30 Lunch & VvL Ledenvergadering in the 'La Place' restaurant within the OBA

13:30-14:15 Liesbeth De Mol (Gent, Belgium)

Title: The mathematics of Homo Sapiens and its limitations: Emil Post's views on symbolic logic and computation

In 1936 Alonzo Church, Emil Post and Alan Turing published a paper in which they each proposed a 
thesis which is now known as the Church-Turing thesis. This talk will focus on Post's contributions
in this context. It is shown how his method of "generalization through simplification" in the 
early 20s resulted in devices that are less intuitively appealing than Turing machines but 
nonetheless convinced him of the absoluteness of the unsolvability of certain decision problems 
and how it was this work that resulted in his criticism of Church's ``definition'' and the 
publication of his 1936 formulation 1. Some attention will be given to a program of generalizations
of Post's thesis he announces in his 1936 paper and how this resulted in his modifications of the 
Turing machine concept as described in some letters to Church.

14:15-15:00 Jan van Leeuwen (Utrecht, The Netherlands)

Title: Turing's impact on understanding computation

Abstract: In 1936 Alan Turing developed a formal notion of computability that would determine the 
future course of computer science. His understanding of universal machines was a basis for the 
design of general-purpose computers. In the 1950's Turing's model of computation and oracles 
proved crucial in understanding computational complexity, a notion that now underlies all our 
thinking of feasible algorithmics. His computational views were a beginning of the algorithmic 
lens that is transforming science today. The very development also led to models that may be more 
efficacious than Turing's for certain features of computation. 
Is there anything beyond Turing's machines?

15:00-15:30 Tea Break

15:30-16:15 Andrew Hodges (Oxford, UK)

Title: Alan Turing: Not only a beautiful mind

Abstract: Alan Turing is often presented as the pure mathematical theorist, whose definition of 
computability gave rise to the idea of the modern electronic computer and to the vision of 
Artificial Intelligence. But his life and work was also full of application and action. He was 
always interested in the practical application of his ideas, and found enormous scope for his 
ambition first in the codebreaking work of the Second World War and then in the planning of his 
own computer project after 1945. His life involved drama and conflict, not least in the events at 
the end of his short life in 1954. These stories are brought together in the play 'Breaking the 
Code', to be performed later in the day, and I will explain the historical basis of the material 
presented on the stage.

16.15-16:30 Tea Break

16:30-17:15 Bennie Mols (Amsterdam, The Netherlands)

Title: From Turing?s Test to Turing?s Tango

Abstract: The Turing Test is centered around the question when it is fair to say that computers 
think. I argue that the Turing Test is outdated because it is too much based on imitating human 
intelligence. Imitating human intelligence has for a long time been the dominating aim in the 
field of artificial intelligence. On the basis of the fundamental differences between the 
(biological) human brain and the (electronic) computer brain I argue that the new challenge is to 
answer the question how artificial intelligence can best help mankind: what is the best tango pair 
of man and machine? Actually, my view goes back to the one of the American computer scientist 
Joseph Licklider, who, already in 1960, pioneered the thinking about what he called ?man-computer 
symbiosis?. In our modern society ?man-computer symbiosis? has become the dominant reality, 
whereas artificial humanlike intelligence, as imagined by Turing and many others, is still nothing 
more than a dream.

17:15-18:30 Dinner Break

19:30-21:45 Theatre Performance by University Players Hamburg: "Breaking the Code" by Hugh 
Whitemore