We are observing ourselves being observed by the painter, and made visible to his eyes by the same light that enables us to see him – Michel Foucault, 1970
Visibility as a concept is more complex in a societal context than in a physical context. From a base standpoint, visibility is the state of being seen. While the concept of societal invisibility can be described as being brought about by social mores causing certain groups of people to either be less present or less outward in society, visibility itself does not come from norms shifting over time. Visibility comes about through continued transgression until being oneself is not considered transgressive. Visibility necessitates making some uncomfortable to achieve a greater goal. It means indicating to society that the discomfort of some or even many is less important than the ability to exist for any marginalized group.
Today, on the Transgender Day of Visibility, it is worthwhile to remember that every day is a day that allies can work to ensure that transgender people are visible. There are myriad methods to do this, but one that is rather easy to do is to push back against any forms of transphobia in day-to-day life. This can mean a variety of things, but it can be standing up against transphobic language. It can mean not supporting individuals or businesses who fund anti-transgender laws and organizations. It can mean supporting trans-owned businesses in one's area. This is obviously far from exhaustive, but action is itself critical. Allyship means working to ensure visibility.