A number of researchers, notably Dayal (2011), have noted that the semantics of pseudo noun incorporation (PNI) is remarkably similar to that of noun incorporation (NI). The difference between PNI and NI lies in the morphosyntax such that NI involves a tighter morphological relation. The question arises as to what gives rise to the semantics of both PNI and NI if it is not in the morphosyntactic structure. We propose that the lack of differentiated Case gives rise to at least one semantic property of (P)NI, namely the availability of a wide range of thematic relations to semantically incorporated elements. We suggest further that this may be the defining property of semantic incorporation. We bolster this claim with evidence from Mandarin Chinese, which has Case, but crucially does not have morphologically differentiated case. We show that full DPs (with undifferentiated Case) have some of the same semantic properties as found in PNI and NI.