Scientific research is difficult to do well, and people are
flawed and biased. As Carl Sagan noted, science is not just an
ideal abstraction, but is very much a human endeavor, and as
such is messy and imperfect. Nature itself is random and quirky
and doesn’t always cooperate with our desires to penetrate its
secrets. The power of science as a tool for understanding the
world comes largely from the fact that it is self corrective –
it doesn’t always get it right the first time, but it has the
potential to fix any mistakes and get it right eventually. Part
of this self-corrective power comes from the humble replication
– scientists repeating the work of other scientists to see if
they get the same results. If a certain result represents a real
effect in the world, it should generally replicate, no matter
who is doing the experiment. If the result represents some
methodological error, or was just a chance result, then it will
not consistently show up in replication. This fact has
particularly plagued parapsycho