At each step along the way, the certainty of stating the situation as fact increases until you reach the top, when you can state with certainty. At the pinnacle of the Hierarchy of Certainty in science is the Scientific Theory. A person can - with all the power of SCIENCE! behind him or her - state a scientific theory as fact.
Someone has an idea and they form a hypothesis*. They then make a prediction, and create methods to analyze and test. If the hypothesis or prediction fails in the testing or the analysis proves either incorrect, the hypothesis and/or prediction gets refined to support the evidence and analysis. Or in the more egregious failures, hypotheses and predictions get completely tossed, and the process starts anew.
After rigorous testing, and the resulting measurable, repeatable and objective evidence is compiled, a scientific law* is formulated.
After one or more laws are established, a means of explaining the law(s) is formulated. THIS IS THE THEORY.
A scientific theory is "a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment."
Who knows, all our current theories might be tossed out as new scientific methods are created to test them. Though, the progression (as far as I know) is that they are getting more and more support as testing methods are created and made more sensitive.
**A scientific law is a distillation of the results of repeated observation.