Opposite is chaos , or disorder. Cosmology is the study of the order in the universe. We take seemingly disparate, disordered phenomena and try to find the underlying order. General idea we have is that the universe is made of matter and energy which behave according to certain physical laws . On the small scale, matter consists of fundamental particles, which interact with one another.
Energy is associated with forces between the particles.
In cosmology, however, we need to use General Relativity. The task of cosmology is to develop a model of the universe, a description of how matter and energy interact through the known physical laws. In other words, the laws of physics permit a lot, they don't tell us that the universe logically has to be a certain way. For this, we need to check our model against the evidence . The model that most closely matches the evidence is the interpretation of the universe that we will prefer.