Evolutionary thought holds that the universe, the quasars, the galaxies, the solar systems, the planets and moons (oh and all of biology too) arose spontaneously by chance events and natural law. How that occurred is uncertain and under scientific investigation. That it occurred is not uncertain, it is a fact. These two different departments of evolutionary thought are disjoint. The fact of evolution does not derive from the particular theories of how it could have happened. It must be that way because there is substantial uncertainty of how it could have happened. Theories of the Solar system evolution, for instance, fall into two broad categories. In the monistic theories, the planets and Sun arise from the same process, such as in Laplace's Nebular Hypothesis. In dualistic theories, the planets and Sun arise from different processes, such as in Buffon's comet theory. These two rival classes of explanation have competed for centuries and as historian Stephen Brush has observed, the time scale for reversing between these two types of explanation has grown shorter and shorter as we approach the present. Hence the origin of the solar system, says Brush, is an unsolved problem. 
This week’s Science magazine provides yet another example of this phenomenon of a multiplicity of explanations in another one of professor Brush’s areas of interest: the evolution of the Earth-Moon system. It is another example of a problem that has required ever increasing complexity of explanation to account for the evidence. Science has two papers on the evolution of the Earth-Moon system, one calling for a larger impactor than usual and a subsequent resonance with the Sun, and the other calling for a faster spinning proto Earth and subsequent resonance between the Sun and Moon. As the perspective explains, the two papers “offer differing solutions to the problem.” Fortunately the fact of evolution does not depend of the science of evolution.
1. Stephen G. Brush, Nebulous Earth: The Origin of the Solar System and the Core of the Earth from Laplace to Jeffreys, (Cambridge: Cambridge University Press, 1996) 4.