sl-outlist-asymmetry

Summary

When checking whether a conclusion is supported, the system treats missing supporters and missing defeaters differently. If a reason that supports a conclusion is missing, the conclusion fails. But if a potential defeater is missing, the conclusion still holds. This makes it possible to set up default reasoning — you can say "assume X is true unless something specifically contradicts it," and that works even before any contradicting evidence has been added to the system.