Construction Grammar has gained prominence in linguistics, owing its popularity to its inclusive approach that considers language units of varying sizes and generality as potential constructions – mentally stored form-function units. This Element serves as a cautionary note against complacency and dogmatism. It emphasizes the enduring importance of falsifiability as a criterion for scientific hypotheses and theories. Can every postulated construction, in principle, be empirically demonstrated not to exist? As a case study, the author examines the schematic English transitive verb-particle construction, which defies experimental verification. He argues that we can still reject its non-existence using sound linguistic reasoning. But beyond individual constructions, what could be a crucial test for Construction Grammar itself, one that would falsify it as a theory? In making a proposal for such a test, designed to prove that speakers also exhibit pure-form knowledge, this Element contributes to ongoing discussions about Construction Grammar's theoretical foundations.