The construction of constructions.

Many kinds of Constructivists (Especially radical Constructivists) argue that nothing exists beyond one'sconstruction. However, what exactly is a mental construct? Most would claim that it is a process that our brain uses in order to organize events and to create meaning from them. However, do we have constructs informing us on what mental construct are? If that is the case, then we do not truly objectively know what a construction is since all we have is the construct. Therefore constructions could be anything! If all there is in life is the construction, then we must admit that we have an objective definition of what a constructivism, incidcentally being forced to admit that there is an objective reality, which in turn makes all constructivists adopt a realist standpoint. Take that Radical constructivism, includingyou, von Glaserfeld!