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Scientists seek concepts and principles, not subjective perspectives. Thus, we cling to a myth of objectivity: that direct, objective knowledge of the world is obtainable, that our preconceived notions or expectations do not bias this knowledge, and that this knowledge is based on objective weighing of all relevant data on the balance of critical scientific evaluation. In referring to objectivity as a myth, I am not implying that objectivity is a fallacy or an illusion. Rather, like all myths, objectivity is an ideal -- an intrinsically worthwhile quest. “One aim of the physical sciences has been to give an exact picture of the material world. One achievement of physics in the twentieth century has been to prove that that aim is unattainable.

“There is no absolute knowledge. . . All information is imperfect. We have to treat it with humility.” [Bronowski, 1973] In this chapter we first will examine several case studies that demonstrate ways in which perception is much less objective than most people believe. Our primary means of scientific perception is visual: 70% of our sense receptors are in the eyes. Thus our considerations of perception will focus particularly on visual perception. We then will examine theories of how perception operates, theories that further undermine the fantasy of objectivity. These perspectives allow us to recognize the many potential pitfalls of subjectivity and bias, and how we can avoid them. Finally, we will address a critical question: can a group of subjective scientists achieve objective scientific knowledge?

Perception: Case Studies
“Things are, for each person, the way he perceives them.” [Plato, ~427-347 B.C., b] What do the following topics have in common: football games, a car crash, flash cards, a capitalpunishment quiz, relativity, and quantum mechanics? The study of each provides insight into the perception process, and each insight weakens the foundation of objectivity.

I was never much of a football fan. I agree with George Will, who said that football combines the two worst aspects of American life: it is violence punctuated by committee meetings. Yet, I will always remember two games that were played more than 20 years ago. For me, these games illuminate flaws in the concept of objective perception, suggesting instead that: 1) personal perception can control events, and 2) perceptions are, in turn, controlled by expectations.

It was a high school game. The clock was running out, and our team was slightly behind. We had driven close to the other team’s goal, then our quarterback threw a pass that could have given us victory; instead the pass was intercepted. Suddenly the interceptor was running for a touchdown, and our players merely stood and watched. All of our players were at least 20 yards behind the interceptor.

Though it was obvious to all of us that the attempt was hopeless, our star halfback decided to go after him. A few seconds later he was only two yards behind, but time had run out for making up the distance -- the goal was only 10 yards ahead. Our halfback dived, and he chose just the right moment. He barely tapped his target’s foot at the maximum point of its backward lift. The halfback