Anyone who has read my blog or Facebook page for any length of time knows that I rarely censor comments. I am happy to argue with anyone, no matter how outrageous their claims, because there’s always a possibility I can convince readers, if not the commentor herself.
Like anyone trained in science, I argue using the principles of basic logic and scientific evidence. But it’s difficult, if not impossible, to argue with laypeople who might understand neither.
No one has to prove elephants can’t fly in order to claim they can’t fly.
It’s not difficult to prove them wrong. That’s easy. To anyone with a modicum of understanding of logic, they’ve made fools of themselves. But it’s difficult to get them to understand that they are wrong, or that they have not been able to support their own claims. What follows, therefore, is a very basic primer on the null hypothesis, the cornerstone of scientific reasoning.
Let’s start with the definition of a hypothesis:
a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.
Most people understand that a hypothesis is a provisional claim and it remains provisional until it can be tested and shown to be true.
It can be a description: Pigs are mammals.
It can be a prediction: Tadpoles become frogs.
It can be a claim of relationship: Light is necessary for plants to grow.
You can generate a hypothesis about nearly anything.
But what many laypeople don’t understand is that science ALWAYS starts with the null hypothesis.
What’s the null hypothesis?
The null hypothesis is that there is NO connection between the elements of any hypothesis.
For the hypotheses above, the null hypotheses are:
Pigs are not mammals.
Tadpoles and frogs are unrelated.
Light has nothing to do with the growth of plants.
The null hypothesis is NOT the negative of the hypothesis. This is where laypeople often get confused. It null hypothesis is ALWAYS the claim that there is no connection.
If you want to claim that pigs are mammals, you must prove they are mammals because the null hypothesis is that there is no connection between pigs and mammals. In other words the BURDEN OF PROOF is on the person who asserts the connection.
Laypeople usually understand this to a certain extent, but because they don’t understand the null hypothesis, they don’t understand who must offer proof.
If you claim pigs are mammals YOU must prove the assertion that pigs are mammals. If I claim pigs are not mammals, I DON’T have to prove it because I am merely stating the null hypothesis that there is no connection and the null hypothesis is ALWAYS true until someone proves it isn’t.
To better understand how this works, it is helpful to use an absurd example.
Suppose I say that elephants can fly. I assert that if you push an elephant off a cliff, it will flap its massive ears and settle safety to the ground.
If you insist that elephants can’t fly, do you have to prove that they can’t? Do you have to push an elephant off a cliff and watch it fall to its death below before you can claim that an elephant can’t fly?
No, because the null hypothesis is ALWAYS that there is NO CONNECTION between elephants and flight.
Here’s a real world example:
Yesterday I noted on my Facebook page that there is no evidence that immediate skin-to-skin contact is necessary for mother-infant bonding. I therefore claimed that skin-to-skin contact is not necessary for bonding.
The lactivists promptly swooped in.
Janet KS vehemently disagreed with me. I wrote:
Please supply scientific evidence that skin-to-skin has had any impact on child mental health at the population level.
She offered what she thought was a clever riposte:
Please supply scientific evidence that skin-to-skin has NOT had any impact on child mental health at the population level.
But all she did was demonstrate that she doesn’t understand how science works. The null hypothesis, the starting point for any claim, is ALWAYS that there is no connection, in this case, no connection between skin-to-skin and child mental health. It does not require proof; it is accepted as true.
The burden of proof is on those who want to assert that skin-to-skin improves child mental health. No one has to prove it doesn’t because the null hypothesis is not the negative of the hypothesis. It is the assumption that there is no connection.
The same thing applies to most of the major claims of contemporary lactivism. If lactivists want to claim that breastfeeding in industrialized countries saves lives, they have to show that it does.
It goes both ways.
If I want to claim that aggressive breastfeeding promotion leads to serious, life threatening neonatal complications, I have to prove that it does. Lactivists don’t have to prove that it doesn’t.
The bottom line is this: science ALWAYS starts with the assumption that there is no connection. If you want to claim otherwise, YOU have to prove otherwise.
