The first known use of the word freedom in a political context dates back to the 24th century BC, in a text describing the restoration of social and economic liberty in Lagash, a Sumerian city-state. Urukagina, the king of Lagash, established the first known legal code to protect citizens from the rich and powerful. Known as a great reformer, Urukagina established laws that forbade compelling the sale of property and required the charges against the accused to be stated before any man accused of a crime could be punished. This is the first known example of any form of due process in the history of humanity.
A presumption assumes that a particular conclusion is warranted unless sufficient evidence exists to show that it is not. If we know nothing at all about a particular matter, then a prevailing presumption provides a conclusion to be accepted unless enough contrary information is presented.”
Presumptions can run in two directions. In a legal system, for example, we could adopt either a “presumption of innocence” that presumes persons to be innocent of committing a rights violation until sufficient evidence of their guilt is presented or a “presumption of guilt” that presumes persons to be guilty of violating rights until sufficient evidence of their innocence is presented. By adopting a presumption of innocence we necessarily accept a greater risk that guilty people will escape a legal sanction than with a presumption of guilt. Conversely, with a presumption of guilt we accept a greater risk that innocent persons will suffer the imposition of a legal sanction than with a presumption of innocence.”
-- Randy Barnett
It is not a given that we must presume innocence, it was not that this was always the case and we need to justify this stance as taking it could mean some crimes go unpunished.
we put the burden of proving liability on the victim because it is widely believed that it is worse for an innocent person to be punished than for a victim to go uncompensated.