1. Chapter 10: When Should Seeing Be Believing?

2. Criteria for Evaluating Observation Claims (pp. 100-103) The criteria for evaluating observation claims provide inductive grounds for evaluating observation claims. Insofar as they provide inductive grounds, no one criterion will conclusively show that the claim should be accepted or rejected, although some of the criteria generally provide stronger evidence than others.

3. Criteria for Evaluating Observation Claims (pp. 100-103) (O1) Was the observer in a position to make the observation? –Failure to be in the right place at the right time provides prima facie evidence that the claim should be rejected. It at least shifts the burden of proof: the alleged observer must explain how he or she could make the observation if he or she was not present at the time. (Surveillance tapes, etc.) –Being present does not show that the observer made the observation. He or she might have been distracted, or there might be other conditions that prevented the observation.

4. Criteria for Evaluating Observation Claims (pp. 100-103) (O2) Were the observation conditions adequate for making an accurate observation? –This is usually a matter of degree and requires a judgment call.

5. Criteria for Evaluating Observation Claims (pp. 100-103) (O3) Did the observer have the appropriate technology to make the observation? If so, did the observer know how to use the technology? –Sometimes simple, unaided observation is not enough. Some of us need eyeglasses to see our computer screens, for example. –Sometimes, special instruments are needed to make observations. To see very small things, we might need a magnifying glass or a microscope. If special instruments are needed to make an observation, the observer must know how to use them.

6. Criteria for Evaluating Observation Claims (pp. 100-103) (O4) Does the observer have the background knowledge needed to interpret what was observed? Does the observer’s claim make sense? That is, is it consistent with or supported by what is known from other sources? –If you can’t identify mosquito larva, you won’t identify the “worms” in still water as mosquito larva. –If an observation claim is inconsistent with something you know on some other basis, you have good reason to reject the observation claim. –If an observation claim is consistent with something you know from other sources, you have some reason to accept it, but not conclusive evidence.

7. Criteria for Evaluating Observation Claims (pp. 100-103) Is the observer free from bias that might influence what he or she believes was observed? –Bias can influence what you believe you see— biased persons can misidentify people or objects. –Not all biased observation is bad. If a scientist proposes a hypothesis, he or she is probably a biased observer: the hypothesis guides what he or she looks for. Since others can reexamine the evidence, this “bias” is not a vice. –We’re all biased. We tend to identify people or things in terms of things with which we’re already familiar.