[usmhot]

Actually, taking a theory as true until it is disproved forms the very basis of science. In its strictest sense science admits to everything that has not been disproved.
Naturally, scientists would tend to dismiss any theory for which there is no real evidence and which does not accord with other accepted theories, but pushed to a decision a true scientist would ultimately admit that unless a given theory can be disproved it cannot be entirely dismissed.

In a sense, this forms one of the biggest stumbling blocks for scientists when debating about God, paranormal occurrences, supernatural abilities, etc. A true scientist realises that most of these claims cannot, fundamentally, be disproved and, as a result, will not, in good conscience, simply say they are wrong. However, he/she will discount them on the basis that there is virtually no substantial, repeatable evidence for them.

However, despite claims to the contrary, this basic tenet does mean that science is actually the most open minded discipline.