10 Rules for Scientific Debate

So we're agreed. The phrase "take it at face value" is meaningless to our species...

Life Lessons
    A student recently asked me for some advice.  First off, that’s a pretty unwise thing to do, I haven’t got much of a clue about anything but I appreciate the flattering assumption I’m a fully-fledged grown up.
    The student is locked in an ongoing internet debate with people who just won’t listen to reason.  It’s not a debate about opinion or personal taste either eg "what’s the best superhero film?" (although really there’s no debate there, the correct answer is Spiderman-2).  This is a debate about the nature of reality. 
    Things like: “Do vaccines cause autism?” “Is climate change happening?” “Is the Earth flat?”  “Do ghosts exist?” are all in the Scientist’s sphere of influence because they are all answerable questions. 
So the student asked me how to have a Scientific debate with someone who doesn’t know how to think Scientifically?  An even trickier question would be to do it when the person thinks they can.  It’s a bit of a minefield because everybody automatically assumes their view is correct.  Scientists try to be doubtful of their preconceptions, but they’re only human and everybody is guilty of stubbornness.
    It occurred to me that the skill of debating is something you’re never really taught.  Unless you join a debating society, having a debate/argument/row is something you either figure out for yourself or pick up from watching others.  As a teacher, I never do a lesson on the rules of Scientific disagreement so, I thought, I’ll jolly-well give it a go!  Here are ten simple-sounding (although difficult to implement) rules for finding out who’s right and who’s wrong.

1. Take your time
     In the heat of the moment you always feel the pressure to be as quick-witted as possible.  There’s a gut-feeling that if you don’t come back with a snappy response within seconds you’re going to look foolish.  The effect is compounded when there are spectators present because you’re suddenly on display.  But you must resist the urge to be fast. 
    People take a long time to change their minds so you aren’t going to convince someone in the space of 30 minutes a belief they’ve held for years is wrong.  If you really want to make progress it’s going to take time. A good debate shouldn’t look like a tennis match with arguments bouncing back and forth at lightning speed, it should be a chess match with long pauses in between each move.  
    The longest debate I ever engaged in took something like nine years.  The debate in question was the mothership of all debates: is there a God?  It began at University when I met someone who disagreed with my own convictions and we just went for it.  We would sometimes debate in person but we both agreed we didn’t feel comfortable doing so, because conversations happen fast and this was something to be cautious with.  We kept it entirely in writing and here’s the key thing: eventually, one of us changed their mind.  So remember, there’s no pressure to be a quick thinker.  The important thing is to be a deep thinker.

So we're agreed. It's definitely a chess board.

2. I’m open to your idea, just not convinced yet
    Make it clear the reason you don’t agree with them is that the evidence isn’t good enough.  But also make it clear that if they present good evidence, you’ll listen.  This makes them feel less attacked and therefore more willing to listen to what you have to say.  It also puts the emphasis on evidence rather than personal feelings, intuitions, guesses and upbringing.  You’re not debating the person, you’re debating their claim.
    It’s also wise to establish this early on because it reminds you to keep your own humility.  After all, it’s possible you might be the one who’s mistaken.  I haven’t called this blog “how to win a Scientific debate” because maybe you’re supposed to lose it. 
    Furthermore, by showing that you’re open to correction, it gives your opponent motivation to continue talking.  If you go in insisting they’re wrong, they’re less likely to take you or the discussion seriously. 

3. Certainty vs Confidence
    If the person you’re debating makes a claim, ask if they are 100% certain or 99% confident.  If their answer is "100% certain", I’m afraid the debate is over.  As difficult as this is to accept, you have to walk away, explaining your reason.
    If your opponent is 100% convinced of something that means “there is 0% chance I’m willing to consider the possibility I'm wrong".  You cannot debate a person like that.  You don’t need to be rude about it but they don’t actually want to debate, they just want to think of themselves as correct. 
    Besides, with rule 2 you were willing to listen to them, you have to make sure they’re willing to listen to you.  By reminding them at the start they’ve got to be prepared to admit fault, you increase the chances they might actually do so.  It's also fine to ask the person: why do you believe it?  Find out what convinced them in the first place and what reason, other than gut feeling or preference, actually made them confident?  Just a warning; this can become a battleground because nobody likes to admit when they don’t have a good reason for something.

4. Agree who shoulders “The burden of proof”
    If a person is claiming the existence of werewolves, the way the debate has to run is: they give evidence for werewolves.  They are claiming the fact so it’s up to them to provide proof.  You don’t have to prove the non-existence of werewolves.  After all, it’s not feasible to scour every square inch of the Universe and find out if there’s a werewolf somewhere, that’s not how evidence can work sensibly.  Instead you have to assume “no werewolves...until proven otherwise”.  If you’re the one claiming something however, the burden of proof is on you.
    Sometimes the burden of proof is on both people simultaneously because there are two facts being debated.  For example, if a person claims werewolves are brown and you're claiming they're black, there are two things which need to be addressed separately.  You have go through all their evidence first, then go through all of yours, or agree to take turns. 

So we're agreed. That howling sound was definitely the rest of the EU.

5. What would it take to convince you?
     This is an extension of rules 2 and 3.  In Science any claim can be accepted, no matter how ridiculous, provided there's good evidence.  This means you have to agree on what exactly needs to be shown in order to prove a claim. 
     If the burden of proof lies with them, let them know what evidence would force you to agree.  This puts an emphasis on their providing evidence, rather than just insisting they’re correct.  If they are unable to provide good evidence they have to accept your position is legitimate and that their evidence isn’t as strong as they thought.
     If the burden of proof is on you, ask them what it would take for them to become convinced.  If they can’t think of anything, once again you need to walk away from the debate because it can’t happen.  If they can’t give you a target to hit, there is no point shooting for one.  
     It’s up to both debaters to agree on what counts as good evidence, but remember Sagan’s law: extraordinary claims require extraordinary evidence.
     If a person claims something modest e.g. that a certain politician has committed a crime, it would be unfair to ask them for 50,000 photographs of it happening.  It’s setting an unfeasibly high bar.  But asking them for a few police statements, photographs etc. might be fair game.
     If you are claiming something vast yourself e.g. evolution by natural selection, it’s fine for them to ask for a mountain of evidence to support it.  Or suppose they’re claiming they can talk to the dead.  Simply saying “I can just feel them in the room” isn’t good enough.  Ask them to find out the name and former address of the deceased person, as well as specific details like the colour of wallpaper in their living room.  Then go check!

6. Pin things down to specifics
    If you’re going to be debating something about the world, you have to agree on precise vocabulary.  Vague and ambiguous claims cannot be proven or disproven.  If a person claims “there’s an energy vibration around every person which we can  lock onto with our souls,” that’s a problematic sentence...not because it’s untrue necessarily but because people could interpret it in different ways.
    Find out precisely what they mean by “energy”, “lock onto” and “soul”.  We are debating reality here, which means poetic language and metaphor are to be avoided whenever possible.  That doesn’t mean reality can’t be poetic and beautiful, but if we’re trying to find objective truth, we have to use objective language. 
    If they modify their statement to “a living person has a region of space around their body extending by 1 meter, generated by cell tissue and I can detect it,” that’s something we can work with.  You can now start asking specific questions to pin down exactly what they mean: does broccoli have this region around it as well, or only human cells?  How can you detect it?  How does living tissue generate it, which part of the cell is involved?  Does it interact with the electromagnetic field?  What happens when a cell dies?  Does a cell in a petri dish have the same field? 
    This can often be the point where people get defensive and Scientists are accused of being limited or narrow in their worldview.  Remind the person that you’re willing to believe, you just want to be sure what you’re actually signing up to believe in.  It's not you being closed-minded, they are the one who hasn't made a direct claim yet.  Essentially they've said "there's a blarple for every chocolate spadongus".  OK fine, can you please tell me what you mean by that before I consider whether I agree? 
    If they refuse to give specific definitions at this point you have to walk away.  This is a sign they don't really know what they mean themselves, so there's no chance of them convincing you.
    Oh and if they say things like “well that’s not how I define the word” remind them that words have to be agreed on.   Otherwise I could say “Unicorns exist” but by Unicorns I’m actually referring to “those white flakes which fall from the sky when it’s cold”.  Language is malleable yes, but you can’t repurpose words and expect everybody to agree with your  definition.
    You also need to ask for specific examples.  If a person says “they’ve done studies which have shown...” that’s fine, but ask them which studies.  Who wrote them?  When?  Were they peer reviewed?  Have they been cited a lot?  Have they been reproduced?  How big was their data sample?  How good were their testing methods?  Just because someone published a study claiming something, doesn’t prove the claim is true. 

So we're agreed. Avoid visual metaphors.

7. Keep it testable
     This is one of the most crucial points.  If you’re making a claim about the actual world that means you have to be able to put it to actual test within the world.  Any claim which is untestable has to be discarded as “might be true but no way of knowing.” 
    If a person claims, for instance, that there’s a Universe next to ours but we can’t see it, hear it, feel it, smell it, touch it, or detect its presence with any instrument, “I just know it’s there” this is not a testable claim.  It might be true, but we cannot ever know.
     Now, this doesn’t mean their claim is wrong.  It also doesn't mean human feelings aren't important or worth listening to.  But if a person believes something because of a feeling and nothing else, you have to walk away.  This isn't a debate that can be settled using reason, because it isn't based on reason.  The person has said "I believe because I just do!"
    You can of course try and point out that feeling something is true doesn't make it so.  If a person believes they are Napoleon, this does not make them Napoleon.  Ultimately, any claim based on faith (by definition: believing without evidence) has to be removed from any discussion.  
     
8. Debate one thing at a time
     This seems obvious but as human beings we tend to think in complicated ways and things become spaghettified with little effort.  A simple e-mail from your opponent might contain five different statements.  You have to agree to debate each one individually and resolve it before you move onto the next one.  Don’t be tempted to start debating all five things in one go, deal with one fire before the next.  This also forces them to slow down and examine each claim in scrutinising detail, rather than making sweeping statements.

So we're agreed. Googling the word "juggling" was a good idea.

9. Know your logical fallacies
     There are lots of sneaky tricks people use in debates, often without realising it.  These fallacies are one of the reasons arguments descend into brawls and slagging matches.  There are dozens out there and I can’t possibly list them all, but here are some of the common ones to watch out for. 
    Straw Man Fallacy – If someone makes a claim which is untrue and then proceeds to destroy it, they are building a straw man and tearing it down as an easy opponent. For example, if I said “all Christians believe God is male, but he can’t be because males don’t give birth to life, therefore all Christians are wrong” I’ve just used a straw-man.  The fact is, not all Christians believe God is male, so my following destruction of the claim is irrelevant because the initial premise was false.
    The Genetic Fallacy – When a person claims a piece of evidence can’t be good because the person who discovered it was a bad person or vice versa.  For instance, Harry Harlow conducted awful experiments on rhesus monkeys and gathered a lot of information about them.  Just because he was a monster and his experiments were cruel, doesn’t make their conclusions false.  It can work in reverse too.  A nice, friendly, beautiful person can still be talking garbage. 
    Ad Hominem Fallacy – When you attack the person rather than their claim.  For example, if someone makes a spelling error and you pick up on that rather than what they actually said.  You’re debating their ability to spell and trying to make them look stupid.  It’s a cheap and easy point to score, but are you trying to win minor skirmishes or the entire battle?
    No True Scotsman Fallacy – Also known as “moving the goalposts.”  Bradley Dowden used the example of a man claiming that no Scotsman puts sugar in his porridge.  If he then comes across a Scotsman who does, he responds by saying “well, no true Scotsman puts sugar in his porridge”.  This kind of thing is common when a person is presented with powerful rebutting evidence.  Rather than accept it, they change the definition of their words and decide they never really meant that in the first place.
    Red Herrings – If you’re debating whether vaccines cause autism and they suddenly claim vaccines also cause cancer, ignore it.  The agreed topic of debate is the vaccines-autism link, anything else is a distraction.

10. Disrespect the belief but respect the person
    This is perhaps the most overlooked rule for engaging in a debate.  Nobody likes admitting when they’re wrong (even Scientists) and people will fight tooth and nail, digging stilleto’d heels into the ground to avoid doing so.  A simple rule for life is that the more you get in someone’s face, the less they actually listen to you.
    When we, or our cherished beliefs, are under attack we man the battle stations and adrenaline floods our system.  Adrenaline is very good at making us fighty, argumentative, loud or rude but it doesn’t help us with critical thinking or humility. 
    Even if the person you’re debating is clearly wrong.  Even if the person you’re debating is an idiot who needs to be tuned in about how things really work.  Even if the person’s belief is potentially harmful...they won’t listen to you or to reason if they feel threatened.  It’s a trap of human nature but you have to work with it. 
    Be nice to people, disagree with what they say, but remember they probably like believing what they believe.  Don’t get in people’s faces, get in people’s minds.  This is life and none of us make it out alive.  And, once again to quote the master of Scientific debate, Carl Sagan: “if a human disagrees with you, let him live.  In a hundred billion galaxies you will not find another.”

So we're agreed. We're all in this together.

Image credits
Morph suits: clipartfest
Chess: thisisitaly
Wolf un London: uproxx
Pin target: acceleratestlouis