You have to be really creful when using words like "proof" and "theory" when applied to science. These words have very specific meanings. In science, the word "proof" is properly limited to mathematics. i.e. a "proof" is used to make a statement of mathematical certainty. It applies only to abstract mathematics and not to any application in the "real world".
examples:
1 + 1 = 2 ;abstract mathamatics: provable by definition
1 apple + 1 apple = 2 apples ? NOT provable in this sense of the word. Depends on the nature of apples.
The word "theory" in science is the highest degree of certainty that is applied to a description of any physical phenomena. A theory can never be "proven" in the mathematical sense. It can only be falsified by providing contrary evidence. To remain a "theory" a description must be consistant with all available data; and make predictions of the state of future data. That is, it must predict the outcome of future experiments or findings. Examples of other theories in science are Elctro-Magnetic theory, Hydrodynanic theory, and so on. None of these are "proven". Yet we rarely,if ever, hear it said that "Electro-Magnetic theory is 'just a theory' ". Although makers of "free energy" and perpetual motion" machines may disagree.
If we decide to "formally describe" the method where you can add apples, and the result is always consistant with the number of apples added, we could arrive at "Apple theory". But first, there will be many tests to pass. Are all apples equal ? Big red ones ? those little green ones all count the same ? And what if they are mashed, chopped or eaten ? By the time we cover all of the variations we can think of, "Apple theory" may cover several volumes :)
"Evolutionary Theory" itself, has the same status and is held to the same standard as Elctro-Magnetic theory. And, is somewhat more robust than "Apple theory" as discussed above :) It conforms to all of the available data.
That is not to say that there is no "controversy in the "Field of Evolutionary studies". Within the field, there are hundreds of "Hypothosis" such as "Dinosaurs became birds". These are descriptions of observed data that have not been fully tested. In the future, this hypothosis may be falsified. Perhaps by DNA data, should we ever be able to extract it. Many hypothosis in the field may be falsified, without affecting the status of the theory. For example, if birds did NOT evolve from dinosaurs, it has no real bearing on whether humans evolved from earlier hominids. However, if one of the essential elements of a theory is falsified, the theory must be revisited. For example, if it could be shown that physiological characteristics can NOT be inherited from one generation to the next, Evolutionary theory would be in big trouble, as that affects all aspects of the theory.
Much of the blame for the popular misunderstanding of scientific terms can be layed upon scientists themselves who freely misuse, or atleast use without context, these words when speaking to the general public. Shame on you guys! This gives rise to "lawyer types" who love to jump on statements like : "Evolutionary theory will never be proven". While this is a proper statement; it, and others like it, are commonly used by detractors of the theory for public relations purposes. While a scientist would likely just reply "Well, duh...."; many, at hearing this will interpret, it to mean that there is something deficient about the theory. When really, it is a statement about the nature of ALL theories.
So let me throw in my lot with a naughty but true statement.
<b>There is no proof of evolution And there never will be.</b>
Evidence, on the other hand... There are mountains of evidence. Some of it striking. Like the Archeopteryx fossil known as the "Berlin specimen". Its skeleton is almost indistinguisable, bone for bone, from a miniature "raptor" (of jurassic park fame). But its feathers are 100% Avian ( Bird ) flight feathers. It is such a powerful image, that detractors have for years tried to declare it a fake. But it has passed every test. And more examples of it have also been found.
As biological evolutionary history on earth goes, Archeopteryx is the "middle of the story". But it may be a good place to begin.
