Nothing can be proven scientifically. Science is not about proof, but about preponderance of evidence, as you observed. This might make science suspect to you, but it works very, very well. Nevertheless, we still can study history and learn about what happened. This is one reason science requires reproducibility. If someone claims to have found the fossil of a fish with legs, for example, he better be able to produce that fossil, and there better be legs to be found on it. If someone claims that he can show how homobox genes are essentially the same in all metazoans, other researchers will have to find the same thing, or that researcher is in considerable trouble. "The first principle is that you must not fool yourself, and you are the easiest person to fool." - Nobel Laureate physicist Richard Feynmann (I do not mean any person in particular, BTW) I hope we all enjoyed it and learned a little from it.