A problem when reacting to a contribution as rich and as highly interesting as Pienemann's paper, is that it is much easier to react to what's not in it than to what is. An example is the relation between the theory proposed and the way linguistic knowledge is acquired: “[Processability theory] … is not designed to contribute anything to the question of the innate or learnt origin of linguistic knowledge or the inferential processes by which linguistic input is converted into linguistic knowledge.” It is not easy to interpret the full consequences of the model if we are not to take into account the inferential processes by which the learner adds new information to his/her system. Maybe here the dividing lines are drawn too strictly: if the hypothesis space of the learner is restricted by the procedures that can be applied, one wonders at what level in the cognitive system these restrictions are located. Does the conceptualizer already know what the system is capable of doing, or is it uninformed (as follows from a strict interpretation of Levelt's proposal of an incremental system without feedforward)? In the latter case, this would mean that the learners/speakers would still try to express their communicative intentions and only later on in the process would things go wrong, for example, because the S-procedure cannot be carried out.