Science is basically based on fact and observations. There is disagreement in science because a fact or observation of one scientist is often challenged by another scientist. Different scientists can form different theories around the same unknown fact, which may lead to disagreements. Disagreements in science are actually fruitful, since a disagreement encourages discussions and further testing of a theory until it is proven, leaving absolutely no room for disagreement. There have been numerous disagreements in science over time. We have listed below the 10 most famous disagreements in science ever.