There is no unique value: it is determined by the collective psychology of economic agents and hence such valuations tend to be on the extreme when there is a collective feeling of euphoria or pessimism. Financial risk modelling, therefore, is far more complex than modelling in physics.
As Pablo Triana mentions in his book,4 “There are no immutable laws when it comes to the values of financial assets… In finance there is no truth. A new reality is created every minute through the unpredictability of utility seeking humans.” The above discussions point to the need for a paradigm change in risk modelling.