Sunday, June 13, 2010

On Falsifiability

"You can't prove a negative."

This statement gets tossed around a lot in arguments, especially arguments that lend themselves to the more abstract and theoretical planes, like "Does God exist?" or "Are we alone in the universe?" In those contexts, it's perfectly true --- you can't establish, once and for all, that X (whatever elusive entity X might be) doesn't exist.

A similar precept goes, "Absence of evidence is not evidence of absence."

But if it's true that you can't prove a negative, why is science news so regularly coming out with stories announcing such proofs? "Danish researchers find no link between thimerosal and autism," say, or "Mozart's music does not make you smarter," or "[G]iving up caffeine does not relieve tinnitus" --- all of these statements imply that something has been shown not to be the case.

I think the difference between those statements and the kind of "proving a negative" that's supposed to be impossible lies in how the questions are phrased. For a hypothesis to be testable, it has to have a set of conditions that must also be true --- and are measurable --- if the hypothesis is true. If you can make a prediction based on your hypothesis --- say, that if it's true that thimerosal in vaccines causes autism in children, then autism rates among school-aged children should fall as people stop using thimerosal in vaccines --- and if that prediction's failing to come true necessarily means your hypothesis was wrong, you can falsify the hypothesis. Based on what happens, your hypothesis can be proved wrong or right.

There's nothing inherently impossible about proving that a hypothesis is not true; usually, the statements that cannot be disproven are so vague, or deal with such a vast array of possibilities (i.e., "Space aliens exist somewhere in the universe") that there's no way to test them.


Stephanie said...

Testability is the key, as you proposed. You have to be able to come up with a reasonable hypothesis that can be tested--and the testable hypothesis must logically lead to the true/false conclusion you want.

The validity of your hypothesis is what makes it testable and it is also what determines the logical conclusion that can be derived from the test.

Alexander Cheezem said...

It's actually a lot more complex than that. For a wide variety of reasons, no research study proves anything. Science, especially psychological and medical science, is mired in an endless swamp of ambiguity.

QuemDixereChaos said...

Hey! I just stumbled upon your comment on my post about Trans Books from like a month ago!

I have heard of Halberstam but not yet read his [is that the correct pronoun? Hir website is pronoun-free, but the wiki page uses male pronouns] work. Definitely seems like an interesting topic though! Let me know if you read it!

I'm going to a genderqueer activism retreat next month, so I'll probably have a lot of reading recommendations to share when I get back.

LetsGetHonest said...

Hello, Lindsay --

I found your blog by looking for the DSM III and feminism; I have a book by Susan Faludi that discussed the editing of a prior version. ...I'm a domestic violence (fill in the blank -- opposite of "perpetrator") and mother who, which now is becoming systemic --after leaving that situation, tough enough, has been in the courts for years, struggling to maintain boundaries.

My family of origin turned against me, in denial, and so obstructed things like renewing the RO, getting child support, refusing to take orders from them (being a 40s+ competent adult), and so on, that a viable profession in music, rebuilt from near-scratch (and welfare) AFTER this was gradually driven into the ground, as legal protections were removed, and the court order required almost weekly contact, with no supervision or anyone to make sure nothing bad happened, with the man who had just recently been getting ready to "off" us, if not himself, which was why he was originally thrown out.

I now know dozens of stories like this; women who became homeless after custody-switch based on what we know is "junk science" diagnoses; their so-called "diagnoses" are "not in the best interests" of their children. So, imagine the trauma of a family member being in the care of a person who has in the past terrorized and threatened you, and made good on some of the threats. That's an increasing population of families now. I have barely seen my own kids for years, and the court orders are basically not safely enforceable, meaning my main task is still, getting free and solvent, but from more people.

Anyhow, nice to find your blog, and here's the lengthy comment on someone else's blog which referenced yours (though not this post):


If you're not in it (and if not, stay away!), FYI, the family law venue these days, and since its start, has been oriented towards psychologizing criminality and its origins include mental health professionals. There's a definite link with feminism.

You sound like a very interesting and dynamic person, keep blogging. Also know, that our country is no longer in the hands of"logical" people, but largely religious-minded psychologists, and I have some data to back up that outrageous claim on my site.

I believe a lot of diagnoses can actually be linked to misogyny and an intent to cover up one form or another of violence against women or children. See this group's history site ( or *.org) they talk about intentionally changing the language. Nor do they care about "falsifiability" -- it's mostly about control and money, I believe.

Sincerely, "LGH"

PS. One reason for the longwindedness is the desire to get the message out. When you've been stalked, and I have this past year, significantly (by the same guy) etc. There's a kind of fore-shortening, long-term planning is sort of counter-indicated in these situations. In other words, I want a track record in case something does "happen."

Anyhow, keep up the blog and have a nice day!