Important issues wide open to discussion are: validation of results, psycho-linguistic relevance of the experimental setup, principled ways of surpassing the contextfree limitations of Lambek grammar (inherited in GraSp), just to mention a few.
already the spin-offs of our project (the collection of non-linguistic learners) do inspire confidence in our tenets, we 12 The learning experiment sketched in Moortgat (2001) shares some of GraSp's features.