From the perspective of science, evolution is a fact, in the same way that gravity is a fact. It can be observed through the fossil record, and the scientific community has no doubts that life on Earth has evolved over time. This again matches gravity, as scientists can readily observe that objects with mass do not float away from the earth and into space unless acted upon by an outside force.
The “theory” part of evolution has to do with the exact explanation of how and why organisms evolve over time. Nobody knows for certain the precise combination of factors that result in evolution over time. This again precisely matches gravity, where nobody really knows exactly and precisely how and why gravity works.
So, scientifically speaking, both gravity and evolution are described by “theories”, which are logical frameworks describing the behaviors, while also presenting possible or probable explanations for the phenomenon. However, the fact that the exact mechanisms behind gravity and evolution are unknown does not mean that they do not exist.
Also, science in no way excludes the possibility that evolution is guided by an unseen force or intelligence, any more so than it excludes the possibility that gravity is caused by individual angels assigned to hold every single person, animal, and grain of sand against the earth. However, while science does not exclude these possible explanations, it is not the realm of science to search for spiritual or supernatural explanations for phenomena. It is the realm of science to search for natural explanations to describe the world around us.
From my perspective, the following are true:
Evolution = Science
Creationism = Faith
Intelligent Design = Philosophy (or faith disguised as philosophy masquerading as science)
And here are some definitions used in the further discussion below:
Scientific Method: principles and procedures for the systematic pursuit of knowledge involving the recognition and formulation of a problem, the collection of data through observation and experiment, and the formulation and testing of hypotheses.
Science: knowledge or a system of knowledge covering general truths or the operation of general laws especially as obtained and tested through the scientific method.
Faith: (1) : belief and trust in and loyalty to God (2) : belief in the traditional doctrines of a religion (3) : firm belief in something for which there is no proof.
Philosophy: a search for a general understanding of values and reality by chiefly speculative rather than observational means.
There should be no debate about any of the above being taught in the appropriate venue. However, Creationism and Intelligent Design have as much place in a Science class as Evolution does in a Religion class. They don’t have anything to do with each other.
However, there is a constant hue and cry, mostly by conservative Christians, to either suppress the teaching of evolution in science class, or to include creationism and/or intelligent design in the same venue. One presumes that this is because many Christians reject evolution outright and so do not