A
theory of language.
Non-utilitarian artifacts, such as complex cave paintings, (the Chauvet,) Venus statues, as well as more effective hand-axes, have been dated back to
50,000 years ago.
The big bang theory concludes that these artifacts indicate that during this time we became distinctly human; the artifacts must be linked to a sudden change in the process of human evolution, as well as the birth of full-blown language.
However, it is good to keep in mind that absence of evidence is not evidence of absence.