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                        Argue!

                 a mediation system 
                 for argumentation 
              with defeasible arguments

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                 Version 19-6-1998

              Developed by Bart Verheij

             Department of Metajuridica
               Universiteit Maastricht
                    P.O. Box 616
                6200 MD  Maastricht
                  The Netherlands

                   +31 43 3883048
          bart.verheij@metajur.unimaas.nl
        http://www.metajur.unimaas.nl/~bart/

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                Financially supported 
                     by the 
               Dutch National Programme 
          Information Technology and Law 
                     (ITeR) 
              project number 01437112

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The Argue!-system has been programmed in Delphi 2.0 for 
Windows 95. It is a research tool. Distribution was not 
intended. It contains bugs. 

Unfortunately, no report exists that describes 
what the Argue!-system can and cannot do.

In the Argue!-system the user can 

1. construct arguments, and
2. adduce counterarguments.

The system can be used to determine which 
sentences are justified, and which are not, relative to 
the arguments provided by the user.

There are three basic data-structures:

1. sentences (in boxes),
2. arrows (connecting sentences), and
3. defeaters (shown as two linked rectangles)

Arrows represent which sentences express reasons for 
other sentences. Defeaters represent which arguments are 
counterarguments to (or challenge) other arguments.

The buttons on the right of the screen can be used to 
add sentences, draw arrows and draw defeaters. 
1. Adding a sentence 
   Click the 'Add sentence'-button (the top button on the 
   right). Click somewhere in the main area. Type a 
   sentence. Press the 'Enter'-key.
2. Adding an arrow 
   Click the 'Add arrow'-button (the second button on the 
   right). Click a sentence (the reason). Click another 
   sentence (the conclusion).
3. Adding a defeater
   A defeater consists of two linked rectangles. Click 
   the 'Add defeater'-button (the third button on the 
   right). Click somewhere in the main area. Drag the 
   pointer (i.e., keep the mousebutton down). The 
   'Challenging Rectangle' of the defeater appears. Click
   and drag a second time. The 'Challenged Rectangle' of 
   the defeater appears.

The pointer-button (the lower one on the right of the 
screen) allows selection and deletion of data. (Deletion 
is buggy though: things not shown might still be 
available to the system.) You can drag sentence-boxes 
by pressing the Ctrl-key if the pointer-button is pressed.

The Argue!-system has two algorithms that help determining 
the justification status of arguments: 'evaluate' and 
'jump'. See the 'Options'-item in the 'Argue'-menu for the 
(adjustable!) difference. Both are in rounds: the 
statuses of the current 'round' are used to compute those 
of the next. The user can assign a preferred justification 
status to sentences by clicking the right-mouse button.

Sentences, arrows and defeaters have statuses, of 
different types. The 'Key to symbols and colors' (see the 
'Help'-menu) shows which. (Note that defeaters not only 
can affect the statuses of sentences, but also of 
arrows.)

Actions that involve the status of sentences are logged. 
The current session is logged in a file named log.txt; 
the logs file of the previous session is renamed to 
oldlog.txt. 

The right-mouse button gives additional functionality, 
e.g., the assignment of statuses. The menu that is shown 
depends on the data-structure that is clicked.

All comments are welcome!

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The argumentation theory underlying the Argue!-system is 
based on CumulA - a procedural model of argumentation with 
arguments and counterarguments [Verheij, 1996].

Verheij, B. (1996). 
Rules, Reasons, Arguments. 
Formal studies of argumentation and defeat. 
Dissertation Universiteit Maastricht. 
A summary and table of contents are available on the 
World-Wide Web at 
http://www.metajur.unimaas.nl/~bart/proefschrift/.

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