Proving Too Much

The fal­lacy of Prov­ing Too Much is when you challenge an ar­gu­ment be­cause, in ad­di­tion to prov­ing its in­tended con­clu­sion, it also proves ob­vi­ously false con­clu­sions. For ex­am­ple, if some­one says “You can’t be an athe­ist, be­cause it’s im­pos­si­ble to dis­prove the ex­is­tence of God”, you can an­swer “That ar­gu­ment proves too much. If we ac­cept it, we must also ac­cept that you can’t dis­be­lieve in Bigfoot, since it’s im­pos­si­ble to dis­prove his ex­is­tence as well.”

I love this tac­tic so much. I only learned it had a name quite re­cently, but it’s been my de­fault style of ar­gu­ment for years. It neatly cuts through com­pli­cated is­sues that might oth­er­wise be to­tally ir­re­solv­able.

Be­cause here is a fun­da­men­tal prin­ci­ple of the Dark Arts – you don’t need an ar­gu­ment that can’t be dis­proven, only an ar­gu­ment that can’t be dis­proven in the amount of time your op­po­nent has available.

In a pres­i­den­tial de­bate, where your op­po­nent has three min­utes, that means all you need to do is come up with an ar­gu­ment whose dis­proof is in­fer­en­tially dis­tant enough from your au­di­ence that it will take your op­po­nent more than three min­utes to ex­plain it, or your au­di­ence more than three min­utes’ worth of men­tal effort to un­der­stand the ex­pla­na­tion.

The non­cen­tral fal­lacy is the eas­iest way to do this. “Martin Luther King was a crim­i­nal!” “Although what you say is tech­ni­cally cor­rect, cat­e­gories don’t work in the way your state­ment is impl – ” “Oh, sorry, time’s up.”

But pretty much any­thing that as­sumes a clas­si­cal Aris­totelian view of con­cepts/​ob­jects is gold here. The same is true of any de­on­tolog­i­cal rules your au­di­ence might be at­tached to.

I tend to get stuck in the po­si­tion of hav­ing ar­gue against those Dark Artsy tac­tics pretty of­ten. And the great thing about Prov­ing Too Much is that it can de­mol­ish an en­tire com­pli­cated ar­gu­ment based on all sorts of hard-to-tease-apart ax­ioms in a split sec­ond. For ex­am­ple, After Virtue gave (though it does not en­dorse) this ex­am­ple of de­on­tolog­i­cal rea­son­ing:

I can­not will that my mother should have had an abor­tion when she was preg­nant with me, ex­cept per­haps if it had been cer­tain that the em­bryo was dead or gravely dam­aged. But if I can­not will this in my own case, how can I con­sis­tently deny to oth­ers the right to life that I claim for my­self? I would break the so-called Golden Rule un­less I de­nied that a mother in gen­eral has a right to an abor­tion.

It seemed un­fair for me to move on in the book with­out at least check­ing whether this ar­gu­ment was cor­rect and I should re-eval­u­ate my pro-choice po­si­tion. But that would re­quire sort­ing through all the weird bag­gage here, like what it means to will some­thing, and whether your obli­ga­tions to po­ten­tial peo­ple are the same as your obli­ga­tions to real peo­ple, and how to ap­ply the Golden Rule across differ­ent lev­els of po­ten­tial­ity.

In­stead I just thought to my­self: “Imag­ine my mother had raped my father, lead­ing to my con­cep­tion. I can­not will that a po­lice­man had pre­vented this rape, but I also do not want to en­shrine the gen­eral prin­ci­ple that po­lice­men in gen­eral have no right to pre­vent rape. There­fore, this ar­gu­ment proves too much.” It took all of five sec­onds.

Some­times a quick Prov­ing Too Much can tear apart ex­tremely sub­tle philo­soph­i­cal ar­gu­ments that have been de­bated for cen­turies. For ex­am­ple, Pas­cal’s Wager also proves Pas­cal’s Mug­ging (they may both be cor­rect, but bring­ing the Mug­ging in at least proves ig­nor­ing their cor­rect­ness to be a rea­son­able and im­pos­si­ble-to-cri­tique life choice). And Anselm’s On­tolog­i­cal Ar­gu­ment seems much less fore­bod­ing when you re­al­ize it can dou­ble as a method for cre­at­ing jelly donuts on de­mand.

In­ter­est­ingly, I think that one of the ex­am­ples of prov­ing too much on Wikipe­dia can it­self be de­mol­ished by a prov­ing too much ar­gu­ment, but I’m not go­ing to say which one it is be­cause I want to see if other peo­ple in­de­pen­dently come to the same con­clu­sion.