Ordinary seeing is based on making distinctions (light-dark, edges between regions of differing brightness, colour or texture). The distinctions you make both imply and are implied by a theory about what is worth attending to and what there is to be seen. In the case of ordinary seeing, these theories are built into the neuron structure of the brain so that neural connections and seeing coemerge through early encounters with sight. For example, perceiving depth perception in photographs is trained, not natural. The same applies analogously to the more general notion of perceiving or noticing. Noticing means making distinctions, constructing and distinguishing foreground and background. What we notice is what we are prepared to notice, both literally and figuratively, and depends on what distinctions we are prepared to make, on what we are attuned to notice. It is structured by what our theories expect, and by the language we have available (not necessarily just verbal language). This is why philosophical issues intrude on any discussion of research. Any rigorous enquiry must concern itself with what is perceived and by whom under what conditions. We cannot escape questions of epistemology (the study of knowing and how it comes about), or ontology (the study of how ideas come into existence) even though they may at first seem abstract and unrelated to professional practice. They turn out to be critical if the enquiry is to be shared with colleagues.