No matter how well one theory fits observations, a new theory might fit them just as well or better, or might fit a wider range of observations.
Learning Goal 3bc
In science, the testing, revising, and occasional discarding of theories, new and old, never ends. This ongoing process leads to a better understanding of how things work in the world but not to absolute truth.
Learning Goal 3d
In matters that can be investigated in a scientific way, evidence for the value of a scientific approach is given by the improving ability of scientists to offer reliable explanations and make accurate predictions.