Ontology has attracted considerable attention in information systems analysis and design (ISAD) research. Ontology is philosophy and bears its own substance and history of debates, which quite often have not been accounted for in information systems research. A more comprehensive consideration of well-known philosophical issues of ontology may help to apprehend precisely the transfer of ontological concepts into ISAD, including insights regarding their limitations and to articulate directions towards further research. In particular, this requires expanding of the scope of current debates in information systems towards the socio-philosophical aspects of ontology. Only then, it will be possible to determine whether ontology can direct the project of theoretical foundation for ISAD. An outline of the critique of the prevailing rationalistic methodical understanding of information systems development in contemporary IS literature illustrates how the indiscriminating borrowing of philosophical presuppositions has encumbered current understandings. Critical reflection upon these presuppositions can get over persuasions and bring about theorisation.