When Massimo Pigliucci passed a fortune teller on a city street one day, he said she asked if he would like his fortune told.

He replied, “Shouldn’t you already know that?”

As part of Darwin Week at SIUC, when the life and work of Charles Darwin are celebrated, Pigliucci, an author and professor with credentials of philosophy and science, spoke Thursday to a full auditorium at SIUC about how people can separate science from fiction in his lecture “Nonsense on Stilts: Why It’s Important to Separate Science from Bunk.”

By drawing a line between more and less provable sciences, he said, as well as by taking a closer look at where information comes from, he said a person can base his or her judgments on information closer to fact rather than “bunk.”

Because there is a vast landscape of sciences, ranging from “good science” to “nonsense,” Pigliucci said, he asks himself before making a judgment whether a scientific theory is good, makes logical sense and matches the data that supports it.

He said theories with little or no data to support them may be considered pseudoscience. At the other end, he said, there is what he calls “very sound science,” such as evolution, biology and climate change theories, because he said the theories involved are sound.

In between, he said, there are theories such as astrology, or the claim that vaccines cause autism.

People should consider what they base their decisions on, Pigliucci said, because philosophers and scientists aren’t the only ones who should be interested in defining pseudoscience.

“Most people seem not to be interested in the question of pseudoscience on a practical perspective because the general antic seems to be ‘well, you know, what’s that going to hurt?’A lot of people get hurt,’” he said.

Pigliucci said because people can be killed due to the prevalence of pseudosciences, it should not be only an academic pursuit to separate science from bunk.

“Every time you hear somebody tell you that this thing works 100 percent of the time, your quality detector should go off,” he said.

Examples Pigliucci gave of questionable sciences, or “bunk,” included the cover of a magazine featuring a pregnant woman with AIDS who said she will not take a drug known to be effective against AIDS, because she doesn’t believe HIV causes AIDS. He said such a choice almost certainly means her baby is going to have HIV.

Controversies involving judgments about the AIDS virus extend past some people’s beliefs that HIV does not cause it, Piggliuci said. An example is the minister of health of South Africa, who refuses to distribute helpful drugs because she feels AIDS is a CIA conspiracy, Piggliuci said.

“As a result, millions of South Africans have been dying,” he said. “It gives an idea of what the harm of believing nonsense actually is.”

Because people’s belief in an expert’s theory can have a a great effect on them, Pigliucci said it is important for a person to examine the expert whose opinion they are considering.

He compared himself to a scientists he was in a debate with once, and went through a checklist of who had more experience, published materials and credentials related to the topic being debated.

“I don’t suggest that you do this for every single controversy you hear about on television or in the newspapers, because there’s not enough time,” he said. “But if it comes down to something like, ‘I need to make a decision, do I vaccinate my child or not?’ That’s a decision that’s personal and that affects you and your child.”

Pigliucci said a person should first examine the arguments on both sides when making a decision of whether the theory is fact or fiction. Because it is not always possible for the average person to judge an argument because of lack “technical know-how”, he said, it is important to look at the experts’ backgrounds.

He also suggested people ask questions about what possible biases experts have, as well as for the expert’s track record.

“This kind of exercise isn’t going to give you a certainty,” he said. “You’re not going to say ‘that guy is definitely right’ or ‘that guy is definitely wrong.’ What it’s going to do is change the odds.”

While what people do with the results of comparing sources is their own choice, those in attendance at the lecture were able to make their own judgments on Pigliucci’s theory on science and bunk.

Jason Faught, a sophomore from Midlothian studying business management, said he felt like Pigliucci’s lecture seemed like an oversimplification of how science should be viewed and how it actually is.

“It did help that he put it in very basic terminology so everyone could understand, but I did think it took away from some of the importance of it,” he said. “I see ignorance of science is a big problem.”

Faught said the author’s emphasis on checking the credentials of an expert used for a source can be compared to writing an academic paper. He said he tries to find multiple sources on more than one side of an argument when writing.

“At the end of it, it’s really just who has the best evidence and is more persuasive,” he said.

Although Pigliucci now focuses on philosophy, his background in science may have helped the attendees trust his perspective.

There was only standing room left in the Student Center Auditorium when Richard Thomas, department of zoology and chair of the Darwin Day committee, said Pigliucci’s background as a biologist makes his presentation more important to the celebration of Darwin.

“The significance of Charles Darwin’s legacy just keeps getting bigger and bigger over the years,” he said. “I’d like to think that Charles would be tremendously pleased that this is how far we’ve come since this day. But maybe he wouldn’t be terribly surprised given the breadth of the foundation he left to us.”

More information regarding Darwin Week can be found at www.darwinweek.siu.edu.