  In this letter, we consider cosmological solutions of bimetric theory without
assuming that only one metric is coupled to gravity. We conclude that any
cosmology can be described by fixing the matter content of the space that we
are not inhabiting. On the other hand, we show that some conclusions can still
be extracted independently of the matter content filling both spaces. In
particular, we can conclude the occurrence of some extremality events in one
universe if we know that they take place in the other space.
