Scientists take great precautions against bias. Scientists, like all humans, have a tendency to see what they expect to see rather than what is really there. But scientists are very careful to design research and experiments in such a way as to exclude bias. For example, in testing drugs, the patients who receive the placebo (“sugarpill”), which does not contain the drug, are not told that the pill is a placebo, otherwise they would assume it will not work and they will report themselves as still being sick. But scientists go further and make sure the assistants who actually administer the placebo do not know that it is a placebo, lest the attitude of the assistant influence the patient’s attitude as well. The placebo usually has a bitter chemical in it, or even a mild sedative, so that the patient will believe that it is the real drug. A large amount of the design and expense of scientific research is to avoid bias.
Charles Darwin had to deal with bias also. His evolutionary theory gave nature, rather than God, the creative role. It is the ideal theory for someone who wants God out of the picture. Was Darwin such a person? Well, not at first; his wife Emma was a moderate creationist, and Charles was sensitive to her opinions, as you might guess. But after their daughter Annie died at a tragically young age, both Charles and Emma were devastated. This deepened Emma’s dependence upon Christianity but pushed Charles into agnosticism. This was years before Charles wrote the Origin of Species.
So Charles must have been biased against creationism and in favor of a theory that would make God irrelevant. But he worked very, very hard to make sure that his bias did not influence his scientific judgment. He spent years gathering information about the variability of traits in populations, and about natural selection, as well as about fossils, biogeography, and other evidences of evolution. The Origin of Species is full of numerous lines of reasoning, each with its own evidences, which lead to an undeniable conclusion. That is, he spent years amassing evidence that would prevent his bias from influencing his results. This is the mark of a true scientist.
Creationists are just the opposite. They hate evolution, and will grab at any shred of information that they can twist into evidence to support their view. They even bring together so-called evidences that contradict one another. For example, they present information that they claim proves the Flood of Noah, then they present information that they claim shows gaps in the fossil record. But if there was a flood, there could be no order in the fossil record in which gaps might appear!
Charles Darwin is an exemplar of the heroic scientist who disciplines him or herself to pursue the truth even when bias presses upon the scientist from his or her personal experience.
This essay will also appear in my website eventually.