Many years ago a student submitted a research paper that I continue to use (without personal information, obviously) in classes as an example today. Unfortunately it's not a positive example. The paper is a ten-page treatise on how the American presidents who died in office were all secretly murdered by the Freemasons.

The student was quite unhappy with the (failing) grade this mess of internet conspiracy theories received. "I did research and cited all of the sources", s/he stated. It was true; the paper was exhaustively cited and clearly represented a good deal of research. The problem – and we/I did cover this in class repeatedly throughout the semester – is that not all "sources" are made equal. Some are legitimate, some are questionable, and some are flat-out nonsense. And back when I was still learning how to teach, it surprised the hell out of me to find that a non-trivial minority of students cannot tell the difference.

In the students' defense, it's difficult to explain how to identify a garbage source. TO some extent it's like the old Potter Stewart "I know it when I see it" obscenity test. My best advice, I think, is to err on the side of caution when the objective is to cite supporting research. Sure, government or major media outlet sources will not always be correct and may be flawed. But if the choice is between the Benghazi story on CNN or a post on something called, it is in students' interest to play it safe. Even if the CNN story is not entirely accurate or comprehensive, no one's going to think you're nuts for relying on a mainstream media account.

This is not a problem limited to students, of course. A sizable number of our fellow citizens have problems smelling bullshit even when their noses are buried in it. To put it charitably, the proliferation of news and information on the internet has exposed an uncomfortably high level of credulity among the public. It's problematic enough that a lot of us intentionally seek out information that confirms what we already believe (and discount or reject contradictory facts) but those of us who do make a real effort to inform ourselves about issues can't tell if what we're reading is total garbage.

Most of you know better than to argue with people in internet comment sections or on Facebook, but tell me if the following sounds familiar. A friend who spends a lot of time on websites with words like "healing" and "wellness" in their name shares this must-read link on Facebook. The article explains how vaccines upset the body's natural rhythms and chakras and enzymes. Vaccines also cause autism and leprosy and gingivitis, according to some really fascinating new findings from Jenny McCarthy. It concludes, based on an argument along the lines of "As a mother, I know what is best for my child", that children should not be vaccinated.

You try to point out politely – perhaps offering your own link that gently debunks this monumental pile of baloney – that the information your friend has provided is not entirely accurate. As you know from experience, this rarely has the desired effect of actually informing the recipient. Instead, your friend says something along the lines of "It's so hard to know what information to trust anymore" or "It looks like there are a lot of good arguments on both sides."

This is one of those classic red flag statements – not unlike "I'm entitled to my opinion" or "I guess we'll have to agree to disagree" – that means "I am clearly wrong but I have no intention of changing my mind." It must be, because taking the statement literally is difficult. "It's so hard to know what to trust." Is it? Is it really? No. It's actually pretty easy.

No, doctors and experts and scientists are not infallible. They and we believe things to be true that later turn out to be wrong. But is the American Medical Association a safer bet than the Spiritual Holistic Wellness Center or the Crunchy Moms tumblr? Yes. Ten times out of ten. People argue that it's healthy to be skeptical of consensus and the establishment in any field, and that's true. However, their skepticism appears to end where the blogs and message boards and pseudoscience collections begin.

I've learned my lesson now. We cover the common characteristics of denialism, pseudoscience, opinion, frauds, and plain old bullshit. Hopefully students leave knowing how to identify those things. Unfortunately this prepares them for a lifetime of frustration from dealing with the millions of Americans who can't.