Figure 1.5: In 1847, a doctor, Ignaz Semmelweis, demonstrated that when he washed his
hands before delivering babies fewer women died from infection. Before this, doctors held
untested beliefs about the causes of disease, such as a person’s behavior, or the air they
breathed. ( 5 )
or supernatural entities, such as the existence or nonexistence of a god. However, science
can be used to examine the effects of these experiences.
The most important message from this chapter is that science is not only a way of knowing
it is also a way of thinking and reasoning. Scientists try to look at the world objectively
- without bias or making assumptions. How? Scientists learn to be skeptical, to question
the accuracy of our ideas. They learn to base their understanding of the physical world on
evidence, reasoning and repeated testing of ideas.
To Think Like a Scientist
To think like a scientist, you need to be skeptical about and question your assumptions,
includingwhatoftenseemslikecommonsense. Questioningideascanoftenleadtosurprising
results. For example, if you ask people whether it’s easier to keep a plastic cutting board
clean or a wooden one clean, most people will think that the plastic board is easier to keep
clean and has fewer germs (Figure1.6).
Why do most people believe that plastic is safer? Probably because we assume that it is
easier to wash germs off plastic than off wood. This assumption is promoted by the makers of
plastic cutting boards and it sounds reasonable. After all, wood stains and looks unhygienic;
plastic cutting boards come out of the dishwasher shiny and clean looking. But is plastic