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4.8 Support versus Co-premise I

The main challenge in mapping multi-layer arguments is putting claims in the appropriate place in the chain (or web). This is particularly difficult when co-premises are brought into the picture.

A common mistake is mapping a supporting reason as if it were a co-premise.

 
Discussion

Example: 

The shadows of the astronauts and their equipment in the Apollo pictures seem to point in different directions.  This suggests that artificial lighting was used and therefore the pictures were taken in a studio on earth. [Based on 5.1]

This passage contains two simple arguments.

The co-premise is really a supporting reason.  One sign that there is a problem is that the Holding Hands rule is violated.


A new co-premise has been added. Notice how the co-premises now conform to the Holding Hands rule.

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Copyright Austhink 2003-2006

 Last updated 15-Mar-2007