If the student has explored all other options and still wish to change supervisors, he or she should talk to the graduate program director. If the supervisor happens to be the graduate program director, the student should talk to the chair of the academic unit. If the student remains uncertain or dissatisfied, he or she should talk to the vice-dean graduate studies of his/her home faculty. Beyond that, the student can talk to the university ombudsperson. The student can request that the exchanges with any or all of these individuals (directors, vice-dean, ombudsperson) remain confidential.
Don Ihde called the hypothesis being 'hyped' and referred to clear evidence about the use of optical tools by, ., Albrecht Dürer and Leonardo da Vinci and others. As well the 1929 Encyclopædia Britannica  contains an extensive article on the camera obscura and cites Leon Battista Alberti as the first documented user of the device as early as 1437.  Ihde states abundant evidence for widespread use of various technical devices at least in the Renaissance and . in Early Netherlandish painting .  Jan van Eyck 's 1434 painting Arnolfini Portrait shows a convex mirror in the centre of the painting. Van Eyck also left his signature above this mirror,  showing the importance of the tool. The painting includes a crown glass window in the upper left side, a rather expensive luxury at the time. Van Eyck was rather fascinated by glass and its qualities, which was as well of high symbolic importance for his contemporaries.  Early optical instruments were comparatively expensive in the Medieval age and the Renaissance.