Contents 
Operations and the Making of Scientific Objects................................. 15 
Evandro Agazzi 

The Role of Emniriral Ortprations and Model Construction in the Ontological Commitments of Science. ....21 
C. Ulises Moulines 

Operational Approach to a Logic of Quantum Physics......... -41 
Peter Mittelstaedt 

An Operational Approach to Quantum Mechanics Avoiding the Problem of Objectification. ...61 
Ernst-Walther Stachow 

An Abstract Scientific Construction to Study Organization and Connection: Networks ....85 
Jacques Ricard 

A Solution for Different Types of Liar Paradoxes................................. 95 
Paul Weingartner 

Operations versus Ontology in the Foundations of Mathematics.... 107 
Gerhard Heinzmann/Ralf Kromer 

On Lorenzen's Constrtictivist/Onprativist Approach to the Formal Sciences. ... 127 
Christian Thiel