This is a fun debate. Thanks, Tim. I am supposed to be working on our gen ed reform. You are *not* helping.
I retort! I would claim that when we say the results of an experiment show a causal relationship, that this relationship is only *probably* true. Experimental results are probabilistic. We reject null hypotheses with a certain degree of confidence; sometimes we're more confident than other times, but that doesn't mean we're more right -- it just means we're more *likely to be* right. Same with other sorts of evidence, especially when a wide variety of evidence collected in many ways in many places and over many many years all points to the same conclusion. We are *more likely* to be right in an attribution of cause when there's a ton of evidence. I teach my students often about converging evidence, because so many things in psychology cannot be examined experimentally. Amass enough evidence from enough different angles and we can feel as confident about a causal chain, in spite of there being no experimental data showing such in humans. I feel as certain about smoking being a causal factor in cancer in humans as I do any experimental result showing a causal factor in anything. And! (More retorting!) Saying that "some people smoke and do not get cancer" doesn't eliminate smoking as a cause -- it only eliminates it as the *only* cause. It's not; we know there are other things that cause cancer and there are other factors that can increase or decrease an individual's risk for contracting cancer from smoking. But none of this belies the role of smoking as a causal factor in cancer. Oh, man. Back to gen ed reform. But this is *way* more fun. m ------- Marc L Carter, PhD Associate Professor and Chair Department of Psychology Baker University College of Arts & Sciences ------- "I have yet to see any problem, however complicated, which, when you looked at it the right way, did not become more complicated." -- Paul Anderson > -----Original Message----- > From: Shearon, Tim [mailto:[email protected]] > Sent: Thursday, February 26, 2009 2:56 PM > To: Teaching in the Psychological Sciences (TIPS) > Subject: RE: [tips] BBC NEWS | Health | Drink a day increases > cancer risk > > Marc- > While I agree with you for the most part, I still think saying smoking > *causes* cancer is a bit problematic given that there are > also huge numbers (large # of data points!) of folks who do > smoke and do not get cancer. Perhaps I don't know the data as > well but it seems to allow for a genetic predisposition > toward cancer, with smoking contributing or triggering, as > much as it allows an explanation that smoking causes cancer > unless you have a genetic predisposition to prevent the > insult from causing cancer. > > Perhaps I'm being a bit persnickety but I tell my students > that the term > *cause* should be reserved for cases where there is > experimental evidence. So saying "nicotine in specific high > doses causes cancer in mice" is acceptable to me but saying > "nicotine causes cancer in humans at the levels of smoking" I > do find problematic - as a scientist (I also tell them > smoking is dumb!). I still prefer to say contributes to > causing cancer- you are absolutely correct that the evidence > is unequivocal re the contributions of nicotine to cancer > whereas the purely correlational alcohol data that is being > used to imply a causal connection to cancer does not rise to > the same level or degree of assurance. > Tim > > -----Original Message----- > From: Marc Carter [mailto:[email protected]] > Sent: Thursday, February 26, 2009 12:52 PM > To: Teaching in the Psychological Sciences (TIPS) > Subject: RE: [tips] BBC NEWS | Health | Drink a day increases > cancer risk > > > If all the data on the carcinogenic and atherosclerotic > effects of smoke > were correlational, I'd agree with you. But they're not. There are > animal models, there are _in vitro_ tissue studies, and there are > complex correlational techniques that all point to the health > effects of > smoking. To claim that smoking "causes" these things is based on far > more than simple correlation. > > That's why I can say smoking "causes" cancer to my students > and not be a > hypocrite. I cannot say (with the same confidence) that > alcohol causes > cancer, or reduces heart disease. > > m > > ------- > Marc L Carter, PhD > Associate Professor and Chair > Department of Psychology > Baker University College of Arts & Sciences > ------- > "I have yet to see any problem, however complicated, which, when you > looked at it the right way, did not become more complicated." > -- Paul Anderson > > urg.edu) > > --- > To make changes to your subscription contact: > > Bill Southerly ([email protected]) > --- To make changes to your subscription contact: Bill Southerly ([email protected])
