No doubt I will be accused of being an arrogant scientist, but here goes... Which of the following sentences makes sense to you?Several commenters took me to task as being a lousy scientist, because I ought to know that parents watch their children and know their children well. I thought I would expand on this thought, as it's clear that many people don't understand how science arrives at particular conclusions. People are really, really lousy at arriving at cause and effect, and it takes very careful controls to demonstrate cause and effect.
"Cosmologists have found several planets rotating around stars quite a distance from earth, but parents disagree."
"Geologists have found that plate tectonics underlies the formation of mountains and the occurrence of earthquakes, but parents disagree."
"Medical scientists have found that thimerosal and vaccines have nothing to do with autism, but parents disagree."
This was a trick question. All 3 statements are nonsensical.
*That's* why rationalists call parents who campaign to ban vaccines the "mercury militia". Right or wrong, it's out of frustration with the lunacy of it all.
(As an aside, I'm a biomedical scientist and new parent. My son has been having *all* of his vaccines on schedule.)
As an example of how I (a scientist) arrive at a conclusion:
I have recently been diagnosed with occipital neuralgia. It's a rather painful disorder that's caused by damage to nerves in the back of my scalp (running up over my ear). Basically, the nerves fire inappropriately, and so I experience severe pain in my head like I'm being struck by lightning (repeatedly) even when there's nothing physically wrong with my head.
My neurologist has prescribed for me a drug called gabapentin that is supposed to help numb the nerves. On my last visit, he asked me the question, "Is the medication working?" Me being a scientist, I literally replied, "I don't know, I haven't done the control." My pain is mostly gone, but occipital neuralgia often spontaneously goes away. So I can't tell if my pain has been reduced because I'm taking the medicine, or if it's been reduced because the neuralgia is receding. (That said, given that the medicine has been shown in clinical trials to reduce the pain of neuralgia, I am going to continue with my dosage for a while before I experiment with reducing my dose). It may be that the medicine is no longer doing anything for me. Or it could be that it is the only thing between me and searing pain. Until I experiment with reducing the dose, I really have no idea.
It's an awful lot more difficult to determine cause and effect if you only have one sample (yourself). In science, we refer to this as n equals 1 (n=1). You have 1 sample. One. One sample tells you very, very little.
Same thing goes with determining causation with a disease in your child. If my son gets sick, I could say, "Well, he caught it at the daycare." He may have caught it at the daycare. Or at the grocery store. Or from the child next door. Or from his grandmother. I don't have enough information, even though I am his father and I watch him carefully. And when his cold resolves, I could say "It's because I gave him orange juice". Or vitamins. Or holy water. Or sunshine. But really, I don't know how quickly he would have gotten better if I had done none of these things. Or all of them.
This is why it is very important to determine things with larger groups of people. Larger groups allow you the power of controls. Using controls are how we determine causation.