Today we're going to be talking about two 
additional fallacies of relevance. 
One of them is what we'll call appeal to 
popular opinion. 
It's related to some versions to appeal 
to authority. 
The other is unlike all the other 
fallacies of relevance that we've looked 
at because Speaker: It's not a deductive 
fallacy, it's a practical fallacy. 
It's a fallacy in practical reasoning. 
In order to see what these two fallacies 
are, let's begin by looking at the 
following clip in which both of them 
occur. 
Speaker: You know if we don't catch that 
fish, we both know there ain't going to 
be any deep sea fishing. 
We'll have to stay on the dock like the 
old people. 
Hold it, hold it, what are you doing 
here? Speaker: What? Speaker: What about 
the other foot? There ain't no sock on 
it. 
Speaker: I'll get to it. 
Speaker: Don't you know that the whole 
world puts on a sock and a sock, and a 
shoe and a shoe? [LAUGH]. 
I like to take care of it one foot at a 
time. 
[LAUGH]. 
Speaker: That's the dumbest thing I ever 
heard in my life. 
[LAUGH] Speaker: It's just as quick my 
way. 
Speaker: Wait a minute, that aint the 
point. 
You see what I'm talk, don't keep doing 
it. 
Listen to me. 
[LAUGH] Suppose there's a fire in the 
house and you gotta run for your life. 
[LAUGH] Your way, all you got on is one 
shoe and a sock. 
[LAUGH] My way, you got on a sock and a 
sock. You see, they're even. 
[LAUGH] Suppose it's raining or snowing 
outside, your way with a sock on each 
foot, my feet would get wet. 
My way with a sock and a shoe on one 
foot, I could hop around and stay dry. 
Speaker: I think you've been hopping 
around on your head. 
Speaker: [LAUGH]. 
Speaker: Wait, wait and, listen to me. 
Speaker: [LAUGH]. 
Speaker: Suppose then the other socks got 
a hole in it. 
Speaker: [LAUGH]. 
Speaker: It doesn't have a hole in it. 
Speaker: I said suppose that it's got a 
hole. 
Speaker: Alright suppose it has a hole. 
Speaker: Alright it's got a hole in it, 
so Speaker:You ain't got another matching 
pair, so what are you going to do? Your 
way, you gotta take off a whole shoe and 
a sock [LAUGH] My way, all you gotta do 
is take off one sock [LAUGH] Speaker: All 
right, if it'll make you happy I'll start 
all over again. 
Speaker: No, no, no [LAUGH] You're 
halfway through Oh, gee get on with it, 
we're in a hurry. 
[LAUGH] You can start doing it the right 
way tomorrow morning. 
Speaker: Older American students might 
recognize the clip that we just saw as a 
clip from the TV sitcom, All in the 
Family, which ran in the United States in 
the 1970s. 
In it, the older character with white 
hair is named Archie, and the younger 
character with brown hair and a mustache 
is named Michael. 
In the clip we just saw, Archie gives 
Michael 3 arguments, 
and each time Archie gives Michael an 
argument, that argument commits a fallacy 
of relevance and Michael attempts to 
rebut or respond to the argument. 
Let's consider the first argument that 
Archie gives Michael. 
When Archie sees Michael putting on a 
sock and a shoe and then proceeding to 
put on another sock, Archie says Don't 
you know that the whole world puts on a 
sock in a sock and a shoe in a shoe? The 
implication being, that since the whole 
world puts on a sock in a sock and a shoe 
in a shoe, Michael should also. 
So, Archie is implicitly giving Michael 
the following argument. 
Premise, the whole world puts on a sock 
and a sock and a shoe and a shoe. 
So conclusion, you ought to put on a sock 
and a sock and a shoe and a shoe, and 
since you're not doing that, you're doing 
it wrong. 
That's the first argument that Archie 
gives Michael. 
Now notice this argument is guilty of a 
fallacy of relevance that's very similar 
to the fallacy committed by some versions 
of appeal to authority. 
Even if it's true, and let's grant for a 
moment that it is true that the whole 
world puts on a sock and a sock and a 
shoe and a shoe. 
That doesn't mean that you ought to do it 
that way as well. 
Now maybe there's a good reason why the 
whole world puts on a sock and a sock and 
a shoe and a shoe, but if there is a good 
reason why the whole world puts on a sock 
and a sock and a shoe and a shoe, then 
that good reason is the good reason why 
you ought to put on a sock and a sock and 
a shoe and a shoe. 
In other words, it's not that the whole 
world puts on a sock and a sock and a 
shoe and a shoe, that explains why you 
want to put on a sock and a sock and a 
shoe and a shoe. 
Rather, if there's a good reason why 
other people put on a sock and a sock and 
a shoe and a shoe, then that very same 
reason is the reason for you to put on a 
sock and a sock and a shoe and a shoe. 
So, this argument right here is no good 
even if its conclusion is true, because 
there's some good reason for the premise 
being true. 
This is an example of appeal to popular 
opinion, or we can say popular practice. 
Sometimes popular practice is a good 
guide to what we ought to do. 
But sometimes it isn't. 
So, is popular practice in this case, a 
good guy, to what we ought to do? Only if 
there's a reason why it's the popular 
practice only if there's a good reason 
why everyone puts on a sock, and a sock 
and a shoe in a shoe. 
Michael obviously doesn't think there's a 
good reason for everyone to put on a sock 
and a sock and a shoe and a shoe. 
So, the fact that the whole world does 
so, assuming it is a fact, is irrelevant 
to him, and he says he likes to take care 
of one foot at a time. 
So, simply because everyone else does it 
differently He thinks, there's no reason 
why he should do it the way they do. 
He's happy to take care of one foot at a 
time, and until Archie can give him a 
good reason for doing what the whole rest 
of the world does, Michael's going to 
take care of one foot at a time. 
Okay. 
Now, let's consider whether Archie can 
give him a different reason. 
A good reason. 
for putting on a sock and a sock and a 
shoe and a shoe. 
Next, Archie tries to give Michael 
another argument for why he should put on 
a sock and a sock and a shoe and a shoe. 
Archie's next argument goes like this. 
Well, suppose you have to leave the house 
halfway into putting on your footwear You 
don't get to put on all your footwear, 
you have to leave halfway. 
Let's say there's a fire and you have to 
run out of the house. 
Now if you put on both your socks first. 
In other words if you're putting on a 
sock and a sock and then a shoe and a 
shoe, then when you have to rush out of 
the house. 
Half way through putting on your 
footwear, your feet won't be even. 
You'll have one sock on each foot. 
But, if you would have been putting on a 
sock and a shoe, and a sock and a shoe, 
then when you have to rush out the house 
halfway through putting on your footwear, 
your feet will not be even. 
You'll have a sock and a shoe on one foot 
and the other foot will be bare. 
Now, i'ts better for your feet to be even 
than not. 
Archie doesn't explicitly say that, but 
clearly he implies it. 
Since it's better for your feet to be 
even than not, It's better for you to put 
on both your socks first, in other words, 
it's better for you to put on a sock and 
a sock and a shoe and a shoe. 
Better to do that than to put on a sock 
and a shoe and a sock and a shoe the way 
Michael's doing it in the video. 
So, is this a good argument for why it's 
better to put on. 
A sock in a sock, and a shoe in a shoe? 
No it's not. 
And what Michael says in response to 
Archie, tells us something about why this 
is not a good argument. 
See the reason this is not a good 
argument is because it starts off by 
supposing a scenario that's very unlikely 
to happen. 
It's very unlikely that halfway into 
putting on your footwear, you'll have to 
evacuate the house because of a fire. 
Now, of course sometimes it's good for us 
to take precautions against scenarios 
that are very unlikely. 
For instance, you might buy health 
insurance to pay for an, any expenses 
that you incur in case of some 
catastrophic illness, 
or flood insurance, to pay for the 
damages that'll occur to your house in 
case of some catastrophic flood. 
Even though it's unlikely that you'll 
become catastrophically sick, or you'll, 
your house will undergo some catastrophic 
flooding. 
Still, the reason it makes sense for us 
to take precautions against those 
scenarios is that, even though those 
scenarios are unlikely, if they were to 
happen, the consequences of not taking 
precautions would be really, really dire. 
Right, getting catastrophically sick 
without having any means to pay for your. 
Treatment would be a terrible thing and 
having your house destroyed without any 
means to recover the loss of it would, 
again be a terrible thing. 
So even though those scenarios are 
unlikely, it still makes sense for us to 
take precautions against their happening 
because if they did happen that would be 
terrible. 
But how terrible would it be for your 
feet to not be even, 
for you to have a sock and shoe and, on 
one foot, and the other foot bare? 
Well, it wouldn't be so bad. 
Certainly not as bad as your housing 
burning down. 
So, what Archie is doing is he's 
appealing to a scenario that's very 
unlikely to happen, 
and then he's showing that if you put on 
a sock and a shoe and a sock and a shoe, 
the costs that you would incur in that 
scenario, while they exist, are not all 
that substantial. 
The costs would just be that your feet 
would not be even. 
So Archie is trying to argue that it's 
better to put on both your socks 1st, by 
appeal to a scenario that's 1st very 
unlikely to happen and secondly even if 
it did happen the costs to you of putting 
on a sock and a shoe and a sock and a 
shoe wouldn't be all that great. 
So that's why this is not a good 
argument. 
And what Michael does in response to 
Archie's argument, is to show that a 
perfectly analogous argument could be 
given in favor of the opposite policy of 
putting on a sock and a shoe, and a sock 
and a shoe. 
Michael says, well look, suppose, suppose 
you're right Archie, that you do need to 
evacuate your house half way into putting 
your footwear on. 
But suppose also that it's raining 
outside. 
Might as well be raining outside. 
That's, that's not significantly less 
likely than your having to evacuate when 
it's not raining outside. 
So suppose it's raining outside [SOUND] 
and you have to evacuate your house 
[SOUND] halfway into putting on your 
footwear. 
Well, if you ave a sock in a shoe on one 
foot, then you can hop around and stay 
dry. 
But if you only have a sock and a sock on 
each foot, then you're going to get wet. 
Once again, Michael shows that this same 
kind of argument appeal to an unlikely 
scenario, and appeal to some. 
Miniscule cost associated with the 
obtaining of that scenario. 
That very same argument could be used to 
favor his way of putting on his socks and 
shoes as it can be used to favor R.G.s 
way of putting on his socks and shoes, 
right? So,since that very same kind of 
argument can be used for either 
conclusion. 
It's not a very compelling argument. 
Either way. 
Appealing to an unlikely scenario which 
if it were to obtain would carry with it 
some minuscule cost, is not a way to show 
that one course of action is better than 
another course of action. 
In this third argument, Archie corrects 
the defects that I just pointed out, in 
the second argument. 
First he appeals to a scenario. 
That's much more likely to occur than the 
scenario of your having to evacuate the 
house immediately, halfway into putting 
on your footwear. 
And secondly, he appeals to a cost that's 
a little more substantial than the cost 
of your feet not being even. 
Let me explain what I mean. 
Archie asks Michael to suppose. 
That Michael finds a hole in his second 
sock, as he's putting his second sock on 
his foot. 
Now, that's not an impossible scenario. 
It's probably, more likely to occur than 
having to evacuate the house. 
Half way into putting on your footwear. 
But suppose you find a hole in your 
second sock while you're putting it on 
your foot. 
Well, if you were putting on a sock and a 
sock and then a shoe and a shoe, finding 
a hole in your second sock Would be easy 
to correct. 
You'd just take off your socks. 
Put on another pair of socks without a 
hole in them. 
And then put on your shoes. 
But, if you were doing things Michael's 
way, and putting on a sock and a shoe, 
and a sock and a shoe. 
Then, you'd have to take off the shoe 
that you already put on your first foot. 
If you found a hole in the sock that's on 
your second foot. 
Since it's easier to remove socks than it 
is to remove shoes, let's suppose, Archie 
concludes it's better to put on a sock 
and a sock and a shoe and a shoe than to 
do it Michael's way and put on a sock and 
a shoe and a sock and a shoe. 
And again the reason it's better is 
because In this scenario, where you find 
a hole in your second sock, it's easier 
to fix it if you would put your socks on 
before putting your shoes on. 
So it's easier to fix a problem that 
crops up in this scenario if you're 
putting on a sock and a sock and a shoe 
and a shoe than it is to fix that same 
problem If you are putting on a sock and 
a shoe and a sock and a shoe. 
Now this argument appeals to a scenario 
that is a lot more likely to happen, I'm 
supposing than the the scenario of having 
to evacuate your house halfway into 
putting on your footwear and it also 
appeals to a cost that is perhaps a bit 
more substantial, a bit more obvious. 
Than the cost of having your feet, 
unbalanced having your feet not be even. 
But, while Michael accepts this argument, 
Michael doesn't rebut this argument, it's 
not clear how compelling the argument is. 
How would we judge the compellingness of 
this argument? How can we tell If this is 
a good argument or not. 
[SOUND] Well, here's what we have to do. 
[SOUND] Think back to Walter's discussion 
of practical reasoning. 
[SOUND] Let's say you're deciding between 
two different courses of action. 
[SOUND]. 
One course of action is putting on socks 
first and the other course of action is 
one foot at a time. 
[SOUND] So those are your two choices. 
Are you going to put on your socks first 
and then your shoes, 
or are you going to put on your footwear 
one foot at a time? 
Well, these courses of action are 
going to have different outcomes, 
depending on The way the world is, right? 
There are different ways the world could 
begin, depending on the way the world is. 
These courses of action will turn out 
differently for you. 
So suppose for instance, you have to 
evacuate your house. 
Halfway into putting on your footwear. 
That's one possible way the world could 
be, and under that scenario you'd be a 
little bit worse off going one foot at a 
time, then you would with socks first. 
At least if it's true that it's a bad 
thing to have your feet be unbalanced. 
But there are many other ways the world 
could be. 
Now, in order to figure out which of 
these two policies is the better one, 
which of these two courses of action is 
the beter one, what we need to do is to 
consider all the different ways that the 
world could be. 
And then, consider what the costs and 
benefits of these policies would be under 
each of those scenarios. 
So let's say that we have five possible 
scenarios, scenario 1 One two three four 
five. 
And under scenario one, your'e a little 
better off putting on your socks first 
than going one foot at a tlme. 
Alright, so let's say putting on your 
socks first, that's a really good thing, 
wheras going one foot at a time. 
It's okay, but not great. 
'Kay, under scenario two let's say 
putting on your socks first turns out 
really badly. 
But putting on your footware one foot at 
a time again turns out okay. 
And so on. 
Now, suppose we discovered that no matter 
what happens, putting your footwear on 1 
foot at a time turns out Okay, whereas 
putting on your socks 1st turns out 
really well under some scenarios but 
really badly under other scenarios. 
Then what should we do? It depends and in 
particular it depends on how likely these 
different scenarios are to a curve, how 
probable they are to a curve. 
If scenario 1 under which putting on your 
socks 1st turns out really well, if 
scenario 1 is really likely to occur, 
let's say there's a 90% chance that 
scenario 1 will occur and scenario 1 it 
turns out really well if you put on your 
socks 1st. 
But not so well if you put on your foot 
wear one foot at a time. 
Well then that's a pretty powerful reason 
to put on a sock and a sock and a shoe 
and a shoe. 
On the other hand, if, under one of these 
scenarios, let's say putting on your 
socks first, results In your death, then 
that's a really powerful reason not to 
put on your socks first. 
Because if putting on your socks first 
could even with a 1% chance result in 
your death, it's probably not worth it. 
Probably better to put on your footwear 
on one foot at a time. 
So, if we're trying to figure out if 
Archie's third argument, compelling or 
not, what we need to figure out is this. 
How likely is it, that you're going to 
find a hole in your second sock? And. 
If you do find a hole in your second 
sock, how much worse is it to have to 
remove your shoe versus removing your 
socks. 
And finally what are the other possible 
outcomes Of putting on a sock and a sock, 
and a shoe and a shoe. 
Versus putting on a sock and a shoe, and 
sock and a shoe. 
We have to consider all of the possible 
outcomes. 
Because, if there's some outcome that has 
even a 1% chance of happening. 
Where the consequences of putting on a 
sock and a sock and a shoe and a shoe are 
catastrophic, 
like let's say you die, 
then that's a pretty good reason in favor 
of doing things the other way. 
Because the advantages to the gain from 
putting on a sock in a sock and a shoe in 
a shoe probably are not great enough to 
compensate for the risk of death, that 
you would undertake if this scenario was 
even 1% likely.