Philosophy of Science Tea-time Seminar

Our seminar is normally held on the 3rd Thursday of every month. Availability of speakers changes this plan quite frequently (so far more speakers than months...)


 
 

Recent speakers and their abstracts




Szecsenyi Tibor ELTE BTK Szimbolikus Logika es Tudomanymetodologia Tanszek
     "A metatudomany hatarai es Godel inkomplettsegi tetelei"


Az eloadas celja a 20. szazadi elmeletfelfogasok (szintaktikai, szemantikai 
es strukturalista) rovid bemutatasa, es a rajuk tamaszkodo fobb 
tudomanyelmeleti es tudomanyfilozofiai kerdesfeltevesek es valaszok elemzese. 
Ennek reszekent megvizsgaljuk a Church-fele eldonthetetlensegi tetel es Godel 
inkomplettsegi teteleinek hagyomanyos ertelmezeset.

Az eloadas vitatemaja a hatarteteleknek az elmeletek nyelvi reprezentaciojanak 
modszerere alapozott uj interpretacioja.

Giovanni Boniolo Istituto di Filosofia, Universita di Padova

MODELS, FICTIONS AND COUNTERFACTUALS

        Someone could consider the topic of the models only an "old hat". 
Right in this way, someone could have thought after the analyses by R. Carnap, 
G. Hempel, E. Nagel, R. Braithwaite. But the criticisms by Hesse, Achinstein 
and Spector, and the proposals by Hesse herself and Black have shown that much 
more could be said; as, in these years, Redhead and Cartwright have pointed 
out, too. 

        Each interpretation is a new point of view and each point of view 
permits to see new aspects, as Popper underlines. The interpretative way I 
will propose, based on fictions, a la H.Vaihinger, is different from both the 
semantical one and Hesse's analogical one. For this reason it should throw 
light on aspects till now neglected or considered insignificant. Nevertheless, 
the principal goal of my discussion will not be an attempt to give an entirely 
new theory of the models, but to insert a fictionalistic theory of them in a 
more general framework which deals with the counterfactuals, too. Obviously, 
this fact does not mean that I disregard the results achieved by the previous 
interpretations, specially by the analogical one.

Michael Stoelzner Institute Vienna Circle, Vienna, Austria

LEVELS OF PHYSICAL THEORIES

The most sublime task of physics is  often  seen  in  presenting,
some  day,  a  world  formula  or  a  simple Theory of Everything
(T.O.E.) that crowns the top of a pyramid of physical laws.  This
view has been propagated by many high energy physicists, particu-
larly by Steven Weinberg. If one examines in how far  the  candi-
dates  for  that  claim  determine  the scenario on lower levels,
quite often cases appear, in which more  depends  on  the  actual
circumstances  (initial  conditions  or constants of nature) than
can be deduced from the higher, more general theory. I will argue
that  laws on lower levels might have been present on higher lev-
els merely as possibilities. Symmetry breakings, which determined
the  actual  values  of  constants  of nature, could have occured
spontaneously in the course of the  evolution  of  the  universe.
Such  a  view  attributes to the physical laws at each particular
level the genuine importance they deserve.

Philosophically it considers the explanation of a given  physical
phenomenon  as  the  primary  quest in physics. In the cases men-
tioned the deductions performable fail to give a  sufficient  ex-
planation.   The understanding of a physical theory is maximal if
it can be  comprehended  as  part  of  a  hierarchy  of  physical
theories. I propose not to base the level structure of physics in
a foggy objective reductionism, but to view it  as  an  interplay
between two elements. Firstly, in the mathematical formulation of
physics a natural layering is automatically given. This order es-
tablished  between  general  concepts and specific situations is,
however, only local and does not  induce  an  entire  pyramid  of
mathematics.  But  secondly, the levels established that way only
become physical theories if one supplements the specific physicsl
circumstances  at  the particular level, for instance the results
of unpredictable phase  transitions  and  fundamental  constants.
Both  elments  serve  two possible simplicity criteria, axiomatic
and relational (from propositions to phenomena) simplicity.

Alberto Zanardo Department of Mathematics, University of Padova, Italy

             BRANCHING-TIME SEMANTICS FOR TEMPORAL LOGICS
 
The basic idea underlying branching-time logic is that, in general,
every moment in time has only one past, but many possible futures.
This leads to pictureing time as a tree or as a set of linear orders
(possible histories, possible courses of affairs) which bear
some connection to each other.

In the logic of linear time, the Prior operators P (it was the case
that) and F (it will be the case that) are generally interpreted in a
standard Kripke fashion. In a branching-time context, instead, these
operators can be interpreted in various different ways and it is
often meaningful to consider other temporal or modal operators and to
combine them with the Priorean ones. Moreover, if the interpretation
of these operators is meant to support a branching-time semantics for
propositional temporal languages, there are different options
also for the evaluation of propositional variables.

For this reason, there are various branching-time semantics
for temporal languages. In the talk, these semantics will be discussed
and compared both from the point of view of model theory and from
the point of view of their adequacy to specify the meaning of
tensed expressions in natural languages.

PLEH CSABA ELTE BTK Altalanos Pszichologia Tanszek

                "Tiszta megismeres" es erdek:
        A megismeres funkcionalista pszichologiaja
                es a tudomany onallosaga


Az eloadas kindulopontja az a vita, amely a mai kognitiv 
pszichologiaban es kognitiv tudomanyban szembeallitja 
egymassal azon felfogasokat, amelyek a megismeres vilagat
az "elvont", "tiszta" reprezentaciok vilaganak tartjak, 
s amelyek minden kognitiv teljesitmenynek kozvetlenul "haszon 
erteket" tulajdonitanak. Ket peldan fogom illusztralni a 
szembenallast:

(1)
Az eszleles modularista felfogasa szemben a tapasztalat es 
"erdek" fuggo perceptualis elkepzelesekkel. (Hogyan jelenik 
meg az onmagukba zart modulok tetelezese mint a 
"veridikus" tukrozes biztositeka?)

(2)
A nyelv keletkezesenek es hasznalatanak "mellektermek elvu", 
reprezentacios felfogasa, szemben az "adaptacios" es kommunikacios 
felfogasokkal.

Az eloadas megprobal kiterni arra, mifele altalanosabb tanulsagokat 
hordoznak ezek a vitak a kovetkezo harom atfogo kerdesre nezve:

(i) mi lehet biztos kiindulasi pont a megismeresben?

(ii) milyen kettos kihatasa van az evolucios gondolkodasnak a mai 
kognitiv gondolkodasra nezve? Hogyan lehet mindket tabor evolucios?

(iii) hogyan bomlik fel ketfele hozzaallasra a klasszikus 
funkcionalista pszichologiai orokseg a mai "szellemi vilagban"?

Roman R. Zapatrin Department of Mathematics, St. Petersbourg

LOGIC PROGRAMMING AS QUANTUM MEASUREMENT

The emphasis is made on the juxtaposition of
(quantum theorem) proving versus quantum (theorem proving). The
logical contents of verification of the statements concerning
quantum systems is outlined. The Zittereingang (trembling input)
principle is introduced to enhance the resolution of predicate
satisfiability problem provided the processor is in a position to
perform operations with continuous input. A realization of
Zittereingang machine by a quantum system is suggested.

Redei Miklos

"Neumann-halok es a logikai fuggetlenseg problemai"

A Neumann-algebra es Neumann-halo fogalmainak folelevenitese utan 
azt a problemat vizsgaljuk, mikor tekintheto egy Neumann halo ket 
reszhaloja - mint kvantumlogika - logikai ertelemben fuggetlennek. 
Egy termeszetes fuggetlenseg definicio es a logikai fuggetlenseg 
problemajanak motivalasa utan allitasokat fogalmazunk, melyek a 
logikai fuggetlenseget kapcsolatba hozzak mas, statisztikus 
fuggetlensegi tulajdonsagokkal. 


Szabo Laszlo ELTE TTK Elmeleti Fizika Tanszek

Az elagazo teridok elmelete es a Greenberger-Horne-Zeilinger-tetel

Egyik kiindulopontunk Nuel Belnap elagazo terido elmelete. Ez az egyetlen 
olyan szigoruan megfogalmazott formalis elmelet, amely lehetove teszi az 
objectiv indeterminizmus koncepciojanak es a relativitaselmeletnek az 
egyesiteset. Ha igaz a kvantumelmelet kovetkeztetese, melyszerint a 
vilagunkban letezik objektiv -- vagyis nem csupan a tudasunk hianyara 
visszavezetheto -- modalitas (indeterminisztikussag), akkor a vilagunk 
modalis strukturajat egy nem-trivialis elagazo terido irja le, vagyis olyan, 
amelyben nem csak egyetlen ag van. 

Az eloadas masik pillere a Greenberger, Horne es Zeilinger (GHZ) altal 
1990-ben bebizonyitott kvantummechanikai tetel, amely egyfajta Bell-tetel, 
valoszinusegekre felirt egyenlotlensegek nelkul. A bizonyitasnak azonban 
vannak gyengesegei, amelyeket  tobben, igy Bohm es Hiley is kritizaltak.

Az elagazo terido elmelet nyelvet felhasznalva sikerult Belnappal 
megadnunk  a GHZ-tetel egy precizebb ujrafogalmazasat. Ebben az uj 
megfogalmazasban sikerult olyan bizonyitast adnunk, amely mentes a 
kritizalt gyengesegektol. A problema altalunk megadott analizisebol az is 
vilagosan kiderul, hogy hol vannak a GHZ-tetel ervenyessegenek pontos 
hatarai.

Mark Notturno Director of Popper Project Central European University "Science and the Institution" FIGYELEM: Új helyszín!

 Abstract This paper traces the 'Institutional' turn in the philosophy of science to the failure of classical foundationalism on the one hand, and to the failure to distinguish between Descartes' methodological scepticism and his rench epistemology' on the other. In so doing, it argues that the institutional approach leads to authoritarianism, since it retains the structure and function of classical foundationalism while leaving the oundations' themselves floating in midair. And it suggests that a better response would be to maintain Descartes' resolution to doubt whatever can be doubted without contradiction, while renouncing his resolution not to accept any thesis or belief that has not been proven. Az eloadas idotartama 50-60 perc, amelyet rovid szunet utan kb. 30-60 perc vita kovet. Az eloadas anyaga (Word 6.0 v. PostScript) elerheto a tanszeki home page-en: ftp://hps.elte.hu/pub/Papers/notturno.doc

ftp://hps.elte.hu/pub/Papers/notturno.ps Idopont: 1997 februar 27., csutortok, 18.00 ora Hely: Budapesti Müszaki Egyetem Tanári Klubja, K. ep. I. em. Az eloadasra a Magyar Filozofiai Tarsasag Tudomanyfilozofia Szakosztalya, a BME Filozofia Tanszeke es az ELTE TTK Tudomanytortenet es Tudomanyfilozofia Tanszeke kozos szervezeseben kerul sor. Minden erdeklodot szeretettel varnak a szervezok.