Consensus Is Part of the Scientific Method
A recent study concluded that the consensus on climate change is real. As stories like this usually do, it provoked a lot of outraged commentary. One of our Facebook commenters, however, responded with a perfectly legitimate question: "And how does consensus fit into the Scientific Method?"
This question, or something very similar to it, is always asked when the issue of scientific consensus is raised. Yet, it might surprise the commenter to learn that scientific consensus is real, and is even a vital part of the scientific method!
I like to imagine the scientific method as resembling the solar system. The planets, traveling in perfect orbits, represent the pillars of the scientific method: Observations, hypotheses, predictions/experiments, and continuous refinements.
What holds all of this together -- the inward tug of gravity in this analogy -- is consensus. We often call it "theory," but that's just a different word for consensus. Every scientific field has a unifying theory: for biology, it is evolution; for chemistry, atomic theory; and for physics, quantum mechanics and general relativity. We could replace the word "theory" with "consensus," and the meaning would essentially be the same.
Theories can, and do, fall apart. Phlogiston isn't real. The Earth isn't at the center of the universe. Maggots don't spontaneously generate on rotting meat.
How did such theories collapse? Going back to our solar system model, the consensus fell apart. Why? Because the planets stopped moving in nice, pretty orbits. Instead, they shot wildly out of the system!
Observations no longer made sense. Predictions weren't coming true. Hypotheses were shown to be wrong. Only a new consensus could pull it all back together again.
That's how science works. The scientific method produces consensus. But, if enough contradictory evidence arises, the consensus falls apart. Eventually, it crumbles completely and is replaced by a new consensus. (For more on this concept, read Thomas Kuhn's The Structure of Scientific Revolutions.)
In the meantime, for anybody who is curious about what the current consensus is in any given field, read a review article or meta-analysis. These articles combine the best, most up-to-date information, and they try to paint a picture about where the field is headed.