Technology Education offers an authentic and invaluable range of skills, knowledge, capabilities, contexts and ways of thinking for learners in the 21st century. However, it is recognised that it occupies a comparatively less defined and more fragile curricular position than associated, but longer established, subjects such as Mathematics and Science. While recognising that no single factor lies behind such a condition, this paper draws upon thinking in the philosophy of technology, technology education and the ontology of artefacts to argue that transformation may be considered as an epistemic source for technology in a similar way to ‘proof’ within Mathematics and ‘interpretation’ within Science. Encapsulating technology's intimate relationship with materials, it is ultimately argued that the transformation of a technical artefact from an ill‐defined into a well‐defined ontological state constitutes a prime source of technological knowledge for pupils. Moreover, it provides an alternative route into further consideration about the nature of the domain, epistemology and curricular identity of the subject.