In the previous lecture, we looked at the 
skeptical regress problem and I kind of 
introduced three different ways of 
solving that problem in practical life 
namely reassuring, guarding, and 
discounting. 
Those are three ways to solve the 
skeptical regress problem in practical 
life. 
And in the next three lectures what we're 
going to do is look at each of these in 
much more detail, more carefully, so as 
to understand how they work. 
Let's begin with assuring. 
Here's an example. 
I assure you that smoking is bad for your 
health. 
If I say, I assure you, 
then I'm trying to get you to accept that 
claim on my authority. 
Now, I might have some reason for saying 
that smoking is bad for your health. 
Namely, I've read the U.S. 
Surgeon General's Report, which sites the 
scientific evidence to show that smoking 
is bad for your health. 
But notice I don't actually say it, 
when I say well, it's obvious that 
smoking is bad for your health, 
or everybody knows that smoking is bad 
for your health, 
or I assure you certainly. 
Clearly, smoking is bad for your health. 
Then what I'm doing is I am trying to get 
you to accept that premise without 
actually citing the Surgeon General, or 
anybody. 
I haven't cited the evidence, I simply 
have indicated to you I do have evidence. 
I do have a reason to believe that 
smoking is bad for your health. 
But I haven't given you what the reason 
is. 
So what good is that? 
It's a lot of good, 
because what it means is that if I don't 
give the reason, you can't question the 
reason. 
If I simply say, everybody believes it, 
it's certainly true, then, you can't ask 
whether those people who believe it have 
any reason to believe it, or whether I 
have any reason to be so certain about 
it. 
If I don't give the reason, I've cut off 
your attack on the reason that I would 
give. 
So, assuring is kind of tricky. 
I say I assure you and if you can trust 
me, that's fine. 
But if you can't trust me, then you 
should be asking, well, what kind of 
reason does he really have. 
Now there are many ways to assure people. 
There are three kinds that we're going to 
look at. 
Authoritative, reflexive, and abusive. 
Let's start with authoritative. 
Authoritative is just what it says. 
It cites an authority. 
So I might say. 
I assure you that smoking is bad for your 
health. 
The Surgeon General, has shown that 
smoking is bad for your health, and I 
cite an authority, the Surgeon General. 
Okay. 
Fine, but, have you seen the studies? 
Have I cited the numbers? 
Have I told you when the studies were 
done, how many subjects, under what 
circumstances, which statistical tests 
were used? 
How do you know its causation instead of 
correlation, and so on and so on? 
No, I just say the Surgeon General has 
shown this and you're supposed to take my 
word for it, that those are good studies. 
Unless, of course, you share my 
assumption that The Surgeon General is 
trustworthy. 
So that's the way an authoritative 
assurance works. 
It sites an authority that the audience 
shares as authority with the other 
person. 
They share the assumption that, that 
authority is trustworthy. 
Now sometimes it's the Surgeon General 
and the Surgeon General is pretty 
reliable, but you also get this kind of 
thing from reporters. 
They say an unimpeachable source close to 
the President, has assured me that the 
President's plans are such-and-such. 
And they cite an unimpeachable source, 
but they won't tell you what the source 
is. 
And they won't tell you how the source 
knew it was true. 
So they're citing an authority, but 
they're not telling you what the 
authority or what reason the authority 
has for what the authority claims. 
Now if you trust that authority then 
that's fine. 
And if authority's reliable, then you 
might be safe. 
But if you don't know who the authority 
is, or where they got their information, 
there can be problems. 
Oh, and here's my favorite, here's my 
favorite. 
I sometimes hear students say, but, 
Professor Shannon Armstrong, my teacher 
in the other course said that, blah, 
blah, [COUGH] blah, blah, blah. 
Well, why do you trust your professors? 
Why do you trust me? 
You shouldn't be trusting me or your 
other professors, anymore than you are 
trusting an unimpeachable source close to 
the President. 
So, you have to trust somebody sometime, 
and you have to decide who you're going 
to trust. 
And then it's going to be okay to cite an 
authority in this kind of assurance, but 
you have to watch out for tricks when 
people start citing authorities that 
aren't really authorities, because even 
the best authorities sometimes do studies 
that aren't very careful and might even 
be wrong. 
A second kind of assurance is what I call 
reflexive, reflexive because it's talking 
about yourself. 
I believe that. 
I know that. 
I am certain that. 
I feel sure that. 
And your citing something about your own 
mental state. 
You feel sure. 
Great. 
You feel sure, but why do you feel sure? 
Notice however, that this assurance works 
because, people don't want to question 
what other people feel sure about. 
If I say, well I feel sure that this is 
going to happen. 
In many societies, it's going to be 
impolite to go, 
well, I don't feel sure. 
Matter of fact, I think you're wrong. 
Or, why do you feel sure?'Cause because 
then you're questioning the person. 
And, if that's impolite, then using this 
type of phrase, I am certain that, will 
get people to shut up and not say 
anything. 
But my favorite is when people say you 
know, I've held this opinion for years or 
I've thought about it year after year. 
It's really bothered me and you know, 
after careful consideration I've come to 
the conclusion that blah, blah, blah, 
whatever. 
And, you are supposed to say well since 
you've thought about it so much I'll save 
myself a lot of trouble of thinking about 
it and trust you and go along with what 
you say. 
Well if you let other people do your 
thinking for you, then that's up to you. 
But you're going to be misled in some 
cases, 
because they've thought about it for 
years and years and gotten themself in a 
tizzy and ended up with the wrong 
conclusion. 
So the fact that somebody has thought 
about it for years doesn't necessarily 
mean it's right. 
But somehow in conversation when you say 
I've thought about it for a long time and 
checked all the sources I could then, 
people take the fact that you've reached 
a certain conclusion to be okay for them 
to reach the same conclusion. 
And that's how this reflexive type of 
assurance works. 
The most fun of all is the abusive 
assurance. 
Here's another example from Monty Python. 
No, no nonsense. 
Maybe he's right. 
Maybe it is nonsense, 
but the point is that he gets you to 
except what he believes by abusing you 
and calling it nonsense. 
An the same thing happens when somebody 
says, nobody but a fool would think 
that!" Everybody knows this. 
If you say, everybody knows it, then 
you're saying, well if you don't know it, 
then you're a dummy. 
And, so, they are abusing you in order to 
get you to agree with them by making a 
conditional abuse that applies to you 
only if you don't agree with them. 
And you don't want to be a dummy you 
don't want to speak nonsense you don't 
want to say something that's stupid. 
So, when somebody says you'd have to be 
stupid to disagree with me about this 
then that's going to incline you to agree 
with them. 
Some of these abusive assurances are a 
little bit more subtle so, it's worth 
mentioning one that's used all the time. 
And this is what might be called, appeal 
to common sense. 
So it's just common sense that such and 
such. 
It doesn't matter what the such in such 
is. 
The point here is simply, that if you 
deny that, then you're telling that 
person that you lack common sense. 
Nobody wants to lack common sense. 
So if I said, it's just common sense 
that, it's just plain common sense. 
People say it all the time. 
But what they're doing is they're abusing 
their opponents, by saying that their 
opponents lack common sense. 
So it's a little bit more subtle, but it 
shows that abusive assurances occur, 
either suddenly or openly, all the time. 
So we've seen three different types of 
assurances. 
Okay? 
The first is authoritative. 
The second is reflexive. 
And the third is abusive. 
And their all used in common speech to 
stop the skeptical request problem. 
So why do we need any of these assurances 
in the first place? 
And the answer is, we've got limited 
time. 
You know, you can't go out and check 
every study. 
You can't go out and look into every 
issue. 
You've just got to accept authorities and 
listen to other people and learn from 
them. 
Or you'll never be able to figure out the 
issues that matter to you in life. 
That tells you why assurances are needed 
in general, but what about particular 
cases? 
Well when you're talking to a certain 
audience, if they share your trust of a 
certain authority, or if they trust you 
when you give a reflective assurance, 
or if what you're saying really is 
something that everybody with common 
sense believes in, then again, it can be 
perfectly fine to use an assurance. 
It saves you the time of having to go 
check out every issue, and it helps you 
avoid the skeptical regress problem in a 
very practical way. 
So assuring can be a really useful tool 
in argument. 
But you have to be careful because 
assurances are also subject to a lot of 
tricks that you have to learn to watch 
out for. 
We've already seen that you can sight 
authorities that are trustworthy and 
that's kind of obvious. 
But something that maybe a little less 
obvious is that people use assurances at 
points in their argument in order to 
distract you. 
If something really is questionable, they 
often say, well that's obvious. 
In order to get you to not pay attention 
to it. 
So when someone says that's obvious, it's 
certain, I'm sure. 
It's worth looking carefully, at what 
their so sure about, and asking yourself 
whether you agree with them? 
Because people try to paper over the 
cracks in their arguments, with these 
assurances. 
At least in some cases, and you have to 
learn to watch out for that. 
Another trick is when assurances get 
dropped. 
People will start off saying, you know, 
he believes this, I believe that. 
And then they drop it, and start talking 
as if it's true. 
Now, my favorite example of this was a 
case a few years ago, when there was a 
person caught in Germany, for 
cannibalism. 
And it started off with the reporters 
saying, well, he, the person accused of 
cannibalism, says that there are lots of 
other cannibals in Germany. 
And then it becomes it is reported that 
there are lots of cannibals in Germany. 
and then it became sources have said that 
as if the source are reliable. 
And, pretty soon they were saying there 
are lots of cannibals in German. 
And it moved from he believes it to there 
are lots of them. 
And that's the trick of dropping the 
assurance in a way that can be 
illegitimate. 
So assurances can be useful and they can 
also be misleading. 
And that's going to be true of all the 
different ways of stopping the skeptical 
regress. 
There can be uses and abuses of all of 
these tricks. 
For assurances we want to have an 
assurance when. 
First of all, somebody might question it. 
Second, the audience accepts the 
authority that is being referred to, 
and third, it would be too much trouble 
to actually cite the study and all the 
evidence and the particular people. 
Assurances are not appropriate when 
nobody would question the claim anyway 
then why are you wasting your time 
assuring people? 
When the authority that you are basing 
your assurance on is not really 
trustworthy because then why should they 
believe your assurances. 
And third when you've got plenty of time 
and it would be really easy to give the 
reason straightforwardly instead of 
simply assuring them. 
So, you've got good and bad uses of 
assurances and I hope we understand what 
they are and how to distinguish them, but 
lets just do a few examples just to make 
sure that we've got the general idea.