If I believed the Earth was slowly turning into cheddar cheese, I could invoke this theory to explain a lot of things. Why is the rat population in our major cities growing so quickly? Earth cheesification is providing more rat food. Why have there been so many earthquakes lately? The cheesification of the tectonic plates has made them less resistant to sudden shifts. Why are glaciers melting? The freezing point of cheddar cheese is lower than that of water; as the Earth at the poles undergoes cheesification, the unfrozen cheese is causing a slight warming of the ice sheets from below, resulting in unusual levels of melting.
I could go on like this for a long time, I suppose. At some point, however, you would confront me with some natural fact that I could not logically account for by means of my cheese theory. In other words, even the greatest faith in this underlying assumption could never withstand all possible evidence.
If, however, we could devise a theory that might literally be able to repel absolutely any possible counterevidence, then we would have accomplished something truly diabolical: an unfalsifiable theory. If we could indeed devise such a theory, then we could run wild explaining anything and everything, and absorb absolutely any eventuality, without ever needing to question our faith in the underlying hypothesis.
Then we would be at liberty to publish headlines such as this
: “Research suggests warmer summers could be causing colder winters.” This conjecture, brought to you via the magical theory of global climate change, is reported as though it is the most plausible explanation of the peculiar fact that Canadian winters do not appear to be getting any warmer.