ELFT HÍRADÓ

[Laszlo E.Szabo <leszabo AT hps.elte.hu>]

Department of HISTORY AND PHILOSOPHY OF SCIENCE
Eotvos University, BudapestPazmany P. setany 1/A Budapest
Phone/Fax: (36-1) 372 2924 
Department's Home Page:http://hps.elte.huhttp://hps.elte.hu

PHILOSOPHY OF SCIENCE COLLOQUIUM                
Room 6.54 (6th floor) Monday 4:00 PM 

March Program

 4 March 4:00 PM 6th floor 6.54 
Language: Hungarian

O z s e b   H o r a n y i 
Department of Communication Studies
University of Pecs

Leteznek-e propoziciok?

Ugy latszik, hogy ez a logika tortenetenek tanusaga szerint
regi kerdes manapsag, ebben a naturalizalt vilagban, ujra
aktualissa valt. Az eloadas nem
csak letezesuk mellett fog ervelni, de ervei sem lesznek
mai keletuek. Legfokeppen
a diszkusszio kedveert: hatha utobb mindannyian tisztabban
latunk!

 11 March 4:00 PM 6th floor 6.54 
Language: English, except all participants speak Hungarian

G a b o r   E t e s i^{\star  \dagger } (lecturer) and
I s t v a n   N e m e t i^{\dagger }
\star         Yukawa Institute, Kyoto University, Japan
\dagger Alfred Renyi Institute of Mathematics, Budapest

General relativistic- (and/or quantum-) computability; computing
non-Turing-computable functions in Malament-Hogarth spacetimes

It used to be a (meta) theorem of mathematical logic that
mankind will never know that ZFC (which forms the foundation
of mathematics) is consistent, assuming it is. We will argue
that this meta-theorem is gone, it is no more provable.
We will report on (convergent) results of various research
groups at various parts of the world coming, independently,
to the same conclusion which is, roughly, that Turing computability
may not (after all) be the final limit of the capabilities
of artificial computing devices. Some of the above mentioned
researchers are e.g. Hogarth (Cambridge), Malament, Earman,
ourselves, Kieu (Australia), F. Tipler, to mention only
a few.

We investigate the Church--Kalmar--Kreisel--Turing Theses
concerning theoretical (necessary) limitations of future
computers and of deductive sciences, in view of recent results
of classical general relativity theory. We argue that (i)
there are several distinguished Church--Turing-type Theses
(not only one) and (ii) validity of some of these theses
depend on the background physical theory we choose to use.
In particular, if we choose classical general relativity
theory as our background theory, then the above mentioned
limitations (predicted by these Theses) become no more necessary,
hence certain forms of the Church--Turing Thesis cease to
be valid (in general relativity). (For other choices of
the background theory the answer might be different.)

We also look at various ``obstacles'' to computing a non-recursive
function (by relying on relativistic phenomena) published
in the literature and show that they can be avoided (by
improving the ``design'' of our future computer). We also
ask ourselves, how all this reflects on the arithmetical
hierarchy and the analytical hierarchy of uncomputable functions.
(We note that the goal of ``computing the uncomputable''
is distincly more modest than executing so called supertasks.
Indeed, we do not claim possibility of the second.)

A paper advocating carefully and it detail the view we adopt
here -- that developments in the background physical theory
can influence profoundly the fundamentals of the theories
of computability and logic -- appeared in Bull. Symbolic
Logic Vol. 6 No 3 (2000), pp.265-283 by Deutsch et al. Our
paper on this subject is available on the following internet
address: 
[http://ipsapp008.lwwonline.com/ips/frames/menu.asp?J=4779&S=36698&M=40800#]
A further useful reference is Hogarth, M.: ``Predictability,
Computability, and Spacetime'', pp.1-123, available from
[mh10026 AT cam.ac.uk].

 18 March 4:00 PM 6th floor 6.54 
Language: Hungarian

T i h a m e r   M a r g i t a y 
Department of Philosophy and History of Science
Technical University of Budapest

Quine, megismeres es kognitiv szabadsag
(Quine, cognition and cognitive freedom)

Ket alapveto tapasztalatot minden ismeretelmeletnek szem
elott kell tartania. Egyreszt, az emberek meglehetosen kulonbozo,
inkompatibilis nezeteket vallanak - azaz tekintenek tudasnak
-, masreszt, ugy tunik, megsem lehet barmit gondolni a vilagrol,
azaz nem fordul elo minden logikailag lehetseges nezet.
Ezt a ket szempontot osszekapcsolhatjuk, ha az ismeretelmelet
alapkerdeseit - mi a tudas, es hogyan dontheto el egy hitrol,
hogy tudas-e? - a szabadsag segitsegevel fogalmazzuk meg.
Mennyiben all szabadsagunkban azt tekinteni tudasnak, amit
akarunk, illetve azt tudni, amit akarunk? Nyilvan mar csak
az elozoek alapjan is feltetelezhetjuk, hogy bizonyos kenyszerek,
illetve feltetelek korlatozzak e szabadsagunkat. Ebben az
osszefuggesben az ismeretelmeleti elemzes feladata e korlatok,
feltetelek felderitese, es a kognitiv szabadsag hatarainak
felterkepezese. Milyen korlatok akadalyozhatjak meg, hogy
a legvadabb kepzelgeseinket tudasnak tekintsuk, es milyen
szabadsag all az alkoto fantazia rendelkezesere? Az eloadasban
a quinei meghatarozatlansagi tezisek (aluldeterminaltsag,
holizmus) altal biztositott kognitiv szabadsagot vizsgalom.

 25 March 4:00 PM 6th floor 6.54 
Language: Hungarian

G a b o r   F o r r a i 
Department of Philosophy
University of Miskolc

Ideak es korpuszkulak: Locke tudomanyfilozofiaja
(Ideas and Copuscules: Locke's philosophy of science)

A klasszikus arisztoteleszi felfogasban a tudomany szuksegszeru
igazsagokrol tokeletesen bizonyos ismereteket nyujt. A modern,
durvan hume-ianus felfogasban, a tudomany kontingens igazsagok
fallibilis ismereteben all. Az eloadas azt kivanja bemutatni,
hogy Locke milyen szerepet jatszott a modern nezet kialakulasaban.
Diohejban a kovetkezot. 

Ismeretelmeleti fomuve azzal a rendkivul pesszimista konkluzioval
zarul, hogy a termeszetrol nem lehetseges tudomany, s e
pesszimista konkluziotol a tudomanyos ismeret fogalmanak
modern atertelmezese reven lehetett legkonnyebben megszabadulni.
Az eloadas kozpontjaban az a kerdes all, hogy mikent jut
Locke erre a pesszimista konkluziora. Ennek kifejtesehez
azonban nemcsak Locke-rol kell majd beszelnem, hanem a skolasztikus
es a descartes-i tudomanyfelfogasrol, valamint a korpuszkularis-mechanista
termeszetkeprol is.

____________________________
 The 60-minute lecture is followed by a 5-minute break. Then
we held a 30-60-minute discussion. 
The participants may comment the talks and initiate discussion
on the Internet. The comments should be written in the language
of the presentation. 
The organizer of the seminar: Laszlo E. Szabo 
-- 

Laszlo E. Szabo
Department of Theoretical Physics
Department of History and Philosophy of Science
Eotvos University, Budapest
H-1518 Budapest, Pf. 32, Hungary
Phone/Fax: (36-1)372-2924
Home: (36-1) 200-7318
Mobil/SMS: (36) 20-366-1172
http://hps.elte.hu/~leszabo