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It's been a long and winding road as the 
Beatles used to say, but we're finally at 

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the last stages of reconstructing 
arguments. 

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We've looked at stage one, which is close 
analysis. Stage two which is get down to 

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basics. Stage three which is sharpen 
edges, stage four is organize parts, and 

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we are doing stage five which is fill in 
gaps and we'll also get to stage six 

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which is conclude. 
Stage five really consists of four 

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separate steps. 
First we need to assess the argument for 

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validity. 
Then we need to add suppressed premises. 

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Enough of them to make it valid. 
Then we need to assess those suppressed 

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premises for truth or falsehood. 
And then we need to qualify the 

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suppressed premises in order to make them 
true. 

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The whole goal is to make the suppressed 
premises both plausible for their truth, 

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and enough to make the argument valid. 
So, these steps within the stage really 

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do work in tandem together to try and 
make the argument good. 

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We already learned how to assess 
validity. 

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You simply ask, "Is it possible for the 
premises to be true and the conclusion 

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false, and if so, the argument is not 
valid and if not, the argument is valid." 

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And the way you figure out whether it's 
possible is you try to tell a story or 

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describe a situation and if you can 
describe a coherent situation where the 

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premises are true and the conclusion is 
false, then that show that the argument 

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is not really valid. 
The main topic for today is, what do you 

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do when you assess the argument for 
validity and you find out it's not 

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valid?" And the answer is, you add 
suppressed premises, enough of them to 

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make the argument valid. 
But that might seem like cheating. 

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I mean, you start with an argument that's 
no good, it's not valid, 

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and then you just throw in some extra 
premises in order to make it valid. 

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Why is it that's just distorting the 
argument and making up something that 

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wasn't there? 
The answer is that it's not really bad. 

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And if it were bad, we'd all be in bad 
shape because in everyday life, people 

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always take things for granted. 
They make assumptions. 

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We do it too, 
and if we didn't, boy, our arguments 

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would be really long and boring. 
So there's something to be said in favor 

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of suppressing premises, at least, the 
obvious ones that people really do take 

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for granted. 
But we can also get tricked. 

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People can suppress premises that really 
are questionable, and they just don't 

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want us to see that they're making that 
assumption. 

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So, it's useful to fill out the argument 
with suppressed premises to make sure it 

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really is valid, because that brings 
those assumptions out in the open, where 

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we can assess whether or not they're true 
or false. 

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Another reason to fill in suppressed 
premises is to understand the argument 

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better. 
Because if people suppress premises, then 

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they're showing us some of their 
footprints along the path. 

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But if we really want to know the full 
path that their reasoning followed, we've 

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got to see every single footprint. 
So, 

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the goal of bringing up the suppressed 
premises is to let us trace exactly where 

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the reasoning is from one step to 
another. 

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So there are two goals: One is to trace 
the full path every step and the other 

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goal is to see if there are any 
miss-steps or they are trying to hid 

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something from us by getting rid of one 
of their footsteps, so that's the point 

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of bringing up suppressed premises. 
To accomplish these goals is tricky. 

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You have to find suppressed premises that 
are just strong enough to make the 

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argument valid but not so strong that 
there going to be implausible. 

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because you don't want to ascribe all 
kinds of suppressed premises to the 

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person that they didn't really believe, 
and they didn't really need for their 

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argument. 
So it's kind of like Goldilocks and the 

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Three Bears. 
You want suppressed premises to be not 

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too hot and not too cold, but just right. 
Here's an example from a previous 

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lecture. 
My wife always gives me either a sweater 

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or a board game. 
This box does not contain a sweater 

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because it rattles when it's shaken so 
this time she must have given me a board 

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game. 
We put this in standard form this way. 

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First premise: This box rattles when I 
shake it and that shows you it doesn't 

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contain a sweater. 
Third, she always gives me either a 

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sweater or a board game. 
Conclusion, this time she must have given 

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me a board game. 
Now the first step in this argument is, 

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this box rattles when I shake it. 
And the conclusion there is it doesn't 

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contain a sweater. 
That's the part of the argument we want 

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to focus on here and ask whether that 
argument is valid. 

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The argument is not valid, because it's 
possible for the premise to be true and 

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the conclusion false. 
How can that happen? 

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Well, my wife might be fooling me. 
She might know that I expect either a 

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sweater or a board game, so she puts a 
sweater in the box. 

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And then she puts little rocks around the 
outside so when I shake it, I'll hear 

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something. 
So that's possible, and that shows that 

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the argument's not valid. 
Well, how can we make the argument valid? 

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The question here is, can we add a 
suppressed premise that will turn this 

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invalid argument into a valid argument? 
Here's one that will do the trick. 

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A box that contains a sweater doesn't 
rattle when shaken. 

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Now the argument looks like this. 
This box rattles when I shake it. 

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The box that contains a sweater doesn't 
rattle when shaken, so this box doesn't 

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contain a sweater. 
The explicit premise is that this box 

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rattles when I shake it. 
The suppressed premise is that a box that 

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contains a sweater doesn't rattle when 
shaken and together they are suppose 

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support the conclusion that this box 
doesn't contain a sweater, but do they 

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really support that conclusion? 
Is the argument valid? 

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Well, it's valid only if there's no 
possibility that the premises are true 

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and the conclusions false. 
Without the suppressed premise we saw 

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this might be possible, because my wife 
might be fooling me and putting rocks 

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around the sweater. 
So let's see if that's going to ruin the 

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validity of this argument. 
No! 

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Because if the sweater has got rocks 
around it so it makes noise when I shake 

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it, then the premise that says a box that 
contains a sweater doesn't rattle when 

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shaken turns out to be false. 
So that's not a case where the premises 

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are true and the conclusions false 
because the premise is false in that 

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case. So, by adding this premise, we 
actually succeeded in making the argument 

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valid. 
The problem of course is that validity is 

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not enough for a good argument, as we saw 
several lectures ago. 

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You can have an argument that's very bad, 
when the argument is not sound. What we 

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want really is soundness. 
So, that's why we need the next step, 

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mainly, check the supressed premises for 
truth. 

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Assess whether they're true or false. 
And, if they're not true, then you need 

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to qualify them, in order to make them 
true. 

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because you don't want to claim that the 
person giving the argument was assuming 

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this falsehood, when the didn't have to. 
So let's see if there's some way to 

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qualify this suppressed premise in order 
to make it true. 

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How can we qualify this premise to make 
it true? 

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How are we going to do that? 
Let me think. 

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Oh. 
What about that little word only. 

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You could add that. 
You could say, a box that contains only a 

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sweater doesn't rattle when shaken. 
But the word only, what exactly does that 

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mean? 
We need to clarify that. 

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What exactly is the word only exclude? 
It excludes something, that's the 

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function of the word only, 
but what does it exclude? 

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Well. 
It probably excludes other things that 

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might make the rattling sound like if my 
wife put rocks in the box. 

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So we can clarify this premise by saying 
a box that contains only a sweater and 

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not anything else that might make a 
rattling sound when shaken, won't rattle 

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when shaken. 
Well, is that premise true? 

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Well, you might quibble about details but 
it's close enough for now. 

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What we need to do though is to go back 
and determine whether, when we put that 

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suppressed premise in, the argument's 
valid. 

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And the argument now looks like this. 
This box does rattle when shaken, and a 

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box doesn't rattle when shaken if it 
contains only a sweater and not anything 

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else that makes a rattling sound. 
So this box doesn't contain a sweater. 

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Is that valid? 
Well, no, 

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for the same reason we saw before, 
because my wife might be a trickster who 

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puts rocks around my sweater in the 
birthday present box in order to fool me. 

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Then, the premises can be true, and the 
conclusion false. 

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It's possible that, the first premise is 
true. 

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This box rattles when I shake it. 
And the second premise is true, 

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a box doesn't rattle when shaken if it 
contains only a sweater and nothing else 

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that makes a rattling sound. 
But it's false that this box doesn't 

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contain a sweater, because it still does 
contain a sweater, 

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and it contains a sweater in addition to 
those pesky little rocks that make all 

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that rattling noise. 
Well, if your argument's not valid, we've 

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got to go back to that other step and add 
another suppressed premise. 

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Remember how I told you how these 
different steps within this stage work in 

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tandem and what's happening is you've got 
to check it for validity, add a 

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suppressed premise, recheck for validity, 
maybe add another suppressed premise, and 

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that's what we're doing now. 
So what kind of suppressed premised can 

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we add. 
Well, we could add my wife is not a 

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trickster but basically that amounts to 
she wouldn't put rocks in a birthday 

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present with a sweater in order to fool 
me. 

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So we could make that a little more 
explicit by making the suppressed premise 

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something like this. 
If this box contains a sweater, then it 

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only contains a sweater and it doesn't 
include anything else that would make a 

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rattling sound when shaken. 
And now we can stick that as an extra 

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suppressed premise into the argument. 
Now the argument looks like this. 

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This box rattles when I shake it. 
A box doesn't rattle when shaken, if it 

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contains only a sweater and not anything 
else that makes a rattling noise when 

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shaken. 
If this box contains a sweater, then it 

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contains only a sweater and doesn't 
contain anything that rattles when 

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shaken. 
So this box does not contain a sweater. 

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Now we have an argument that's valid. 
And the suppressed premises are true, at 

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least given our life's not a trickster, 
which she's not, I assure you. 

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And it looks like we have a sound 
reconstruction, 

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just what we were looking for. 
Admittedly, 

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this argument is a lot longer and more 
convoluted than the original, 

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and that shows why people suppress 
premises instead of talking the way this 

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argument goes. 
And of course, many people would be 

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perfectly well convinced by the original 
argument because they share the 

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assumptions that are in the suppressed 
premises. 

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So why do we go through all the trouble 
to go through this process and add the 

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suppressed premises? 
Remember, the reason is that we want to 

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understand the pathway between the 
premises and conclusion. 

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We want to understand how the reasoning 
works step by step by step. 

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And we want to do that because sometimes 
people are going to include suppressed 

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premises that aren't true, 
and we want to bring them out and make 

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those assumptions explicit so that we can 
assess them for truth and falsehood. 

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And when you're talking to somebody you 
trust, you might not have to do that and 

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it's okay to suppress premises. 
But when you really want to know whether 

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the argument's any good, that's when you 
want to fill it out with the suppressed 

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premises. 
The point of going into detail on this 

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example is to illustrate this stage of 
reconstruction. 

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00:13:04,240 --> 00:13:07,061
You want to assess the argument for 
validity, 

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add suppressed premises that make it 
valid. 

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00:13:09,757 --> 00:13:13,393
Check them for truth. 
If they're not true, you qualify them, 

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and then you go back and see whether that 
qualification made the argument not valid 

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anymore. 
And you go back and forth and back and 

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forth until you've got a sound 
reconstruction. 

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The same steps are going to apply to all 
kinds of suppressed premises. 

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00:13:28,734 --> 00:13:32,692
And sure enough, there are all kinds of 
suppressed premises. 

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So let's go through a few examples a lot 
more quickly in order to show the variety 

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of suppressed premises that are assumed 
in arguments. 

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00:13:41,815 --> 00:13:46,260
Here's one example. 
Abraham Lincoln turned 40. 

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On February 12th, 1849. 
Therefore, Charles Darwin also turned 40 

187
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on February 12th, 1849. 
Now, is that argument valid? 

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No chance. 
Of course it's possible for the premise 

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to be true and the conclusion false. 
So we have to add a suppressed premise. 

190
00:14:10,460 --> 00:14:15,856
The suppressed premise is, that Abraham 
Lincoln and Charles Darwin were born on 

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the same day. 
And they were, it happened to be February 

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twelfth, 1809. 
So now, we've filled out the argument. 

193
00:14:22,960 --> 00:14:28,560
Abraham Lincoln turned 40 on February 
12th, 1849. 

194
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Abraham Lincoln and Charles Darwin were 
born on the same day, therefore Charles 

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Darwin also turned 40 on February 12th, 
1849. 

196
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Now is the argument valid? 
No. 

197
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It's still [LAUGH] not valid. 
because Darwin might have died before 

198
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1849. 
So we have to add another suppressed 

199
00:14:49,409 --> 00:14:53,017
premise. 
Mainly, that both Abraham Lincoln and 

200
00:14:53,017 --> 00:14:58,150
Charles Darwin lived beyond 40. 
So now we have a fuller argument. 

201
00:14:58,150 --> 00:15:03,300
Abraham Lincoln turned 40 on February 
12th, 1849. 

202
00:15:03,300 --> 00:15:08,993
Abraham Lincoln and Charles Darwin were 
born on the same day. 

203
00:15:08,993 --> 00:15:16,460
Both of them lived beyond the age of 40. 
Therefore, Charles Darwin also turned 40 

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on February twelve, 1849. 
Now the argument looks pretty good. 

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We had to have two suppressed premises 
but we finally have a valid argument. 

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00:15:25,985 --> 00:15:31,301
And what this shows is that sometimes the 
suppressed premises are purely factual 

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matters. 
In this case that they were born on the 

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00:15:34,452 --> 00:15:37,340
same day and that they both lived beyond 
40. 

209
00:15:37,340 --> 00:15:40,635
So sometimes we have factual suppressed 
premises. 

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00:15:40,635 --> 00:15:45,442
Here's another quick example. 
You ought to obey her because she's your 

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mother. 
Here, the premise is that she's your 

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00:15:48,051 --> 00:15:51,896
mother and the conclusion is that you 
ought to obey her. 

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00:15:51,896 --> 00:15:56,428
Well, is that argument valid? 
No way cause it's possible that she's 

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your mother but it's false that you ought 
to obey her. 

215
00:16:00,136 --> 00:16:04,462
When could that happen? 
Maybe, she was like abusive or stupid or 

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00:16:04,462 --> 00:16:08,133
whatever. 
Then maybe you ought not to obey her even 

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00:16:08,133 --> 00:16:12,859
though she is your mother. 
So we have to add a premise, namely, you 

218
00:16:12,859 --> 00:16:17,028
ought to obey your mother. 
Now we can say she's your mother, you 

219
00:16:17,028 --> 00:16:22,015
ought to obey your mother therefore you 
ought to obey her, but of course that a 

220
00:16:22,015 --> 00:16:27,064
supressed premise you ought to obey your 
mother is questionable because maybe she 

221
00:16:27,064 --> 00:16:30,820
was abusive or stupid. 
So let's add another supressed premise 

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00:16:30,820 --> 00:16:35,562
that your mother was not abusive or 
stupid, of course we also have to qualify 

223
00:16:35,562 --> 00:16:40,364
that moral premise that you ought to obey 
your mother if she's not abusive or 

224
00:16:40,364 --> 00:16:43,135
stupid. 
And now the argument looks like this - 

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00:16:43,135 --> 00:16:48,000
she's your mother, you ought to obey your 
mother if she's not abusive or stupid. 

226
00:16:48,000 --> 00:16:53,250
Your mother was not abusive or stupid. 
Therefore, you ought to obey her. 

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00:16:53,250 --> 00:16:58,779
An notice that here, we added a moral 
premise about the fact that you ought to 

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00:16:58,779 --> 00:17:01,756
obey your mother under certain 
conditions. 

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00:17:01,756 --> 00:17:06,930
Namely, she's not abusive or stupid. 
And the second premise is she was not 

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abusive or stupid. 
So, we have a moral premise and a factual 

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00:17:11,042 --> 00:17:16,216
premise, both being suppressed in the 
argument that you ought to obey her 

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because she's your mother. 
Here's another . 

233
00:17:19,690 --> 00:17:23,388
It's the Sabbath, so you ought to go to 
synagogue. 

234
00:17:23,388 --> 00:17:28,521
Well, that's clearly not valid. 
One suppressed premise is that you're 

235
00:17:28,521 --> 00:17:31,745
Jewish. 
The other suppressed premise is you 

236
00:17:31,745 --> 00:17:35,938
haven't been to synagogue already today, 
on this Sabbath. 

237
00:17:35,938 --> 00:17:39,906
And the third suppressed premise is a 
religious norm, 

238
00:17:39,906 --> 00:17:44,100
mainly Jews ought to go to the synagogue 
on the Sabbath. 

239
00:17:44,100 --> 00:17:49,141
And you need that whole bunch of 
suppressed premises in order to get from 

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00:17:49,141 --> 00:17:54,318
the premise, that it's the Sabbath, to 
the conclusion, that you ought to go to 

241
00:17:54,318 --> 00:17:57,678
synagogue. 
And of course all of those premises might 

242
00:17:57,678 --> 00:18:00,739
be questionable. 
Some people would question them. 

243
00:18:00,739 --> 00:18:05,684
Some people would deny them, but the 
point here is to figure out what's being 

244
00:18:05,684 --> 00:18:08,910
assumed by someone who gave the original 
argument. 

245
00:18:08,910 --> 00:18:13,621
And anybody who says it's the Sabbath, so 
you ought to go to synagogue, seems to be 

246
00:18:13,621 --> 00:18:18,526
assuming you're Jewish, you haven't been 
already, and Jews ought to go to the 

247
00:18:18,526 --> 00:18:23,033
synagogue on the Sabbath. 
So what these suppressed premises do is 

248
00:18:23,033 --> 00:18:28,674
they bring out the assumptions that 
somebody who gave that argument must have 

249
00:18:28,674 --> 00:18:32,363
had in mind. 
The last case is a little bit trickier. 

250
00:18:32,363 --> 00:18:35,906
It has to do with linguistic suppressed 
premises. 

251
00:18:35,906 --> 00:18:41,380
Jen and Bob are first cousins, 
therefore they share a grandparent. 

252
00:18:41,380 --> 00:18:46,635
Now, 
in order to understand that argument, you 

253
00:18:46,635 --> 00:18:51,583
have to know that first cousins always 
share a grandparent. That just follows 

254
00:18:51,583 --> 00:18:55,320
from the definition of what a first 
cousin is. 

255
00:18:55,320 --> 00:19:00,830
But it's not quite so obvious, is that 
biological sisters are female. 

256
00:19:00,830 --> 00:19:06,052
And so, there's even more need to bring 
out that linguistics suppressed premise 

257
00:19:06,052 --> 00:19:09,621
in this case. 
But it's still not necessary to make the 

258
00:19:09,621 --> 00:19:13,388
argument valid. 
It's just not possible that Janet and Bob 

259
00:19:13,388 --> 00:19:16,892
are first cousins, and they don't share a 
grandparent. 

260
00:19:16,892 --> 00:19:22,180
Because the suppressed premise is purely 
linguistic, so it's necessarily true, so 

261
00:19:22,180 --> 00:19:26,733
you can't possibly be first cousins 
without sharing a grandparent. 

262
00:19:26,733 --> 00:19:31,839
Still, the point of bringing out 
linguistic suppressed premises is to show 

263
00:19:31,839 --> 00:19:36,945
every little step along the way. 
The argument might be valid without those 

264
00:19:36,945 --> 00:19:42,190
suppressed linguistic premises, but we 
won't understand why it's valid and why 

265
00:19:42,190 --> 00:19:47,194
the reasoning goes through unless we add 
the linguistics suppressed premise. 

266
00:19:47,194 --> 00:19:49,381
So it's worth doing that. 
Shh. 

267
00:19:49,381 --> 00:19:53,985
Here's a trick. 
Don't tell anybody. 

268
00:19:53,985 --> 00:19:58,590
Okay? 
It's just between me and you. 

269
00:19:58,590 --> 00:20:05,830
You can always make any argument valid 
just by adding a suppressed premise that 

270
00:20:05,830 --> 00:20:11,520
says if the premises are true, then the 
conclusion is true. 

271
00:20:11,520 --> 00:20:16,168
But don't tell anybody, 
because if people start doing that, and 

272
00:20:16,168 --> 00:20:22,390
they start making the argument valid that 
way, with that suppressed premise, we're 

273
00:20:22,390 --> 00:20:26,063
never going to understand the pathway of 
reasoning. 

274
00:20:26,063 --> 00:20:31,578
It makes the argument valid, but it 
doesn't serve the real purpose of adding 

275
00:20:31,578 --> 00:20:36,266
suppressed premises which is to 
understand the pathway of reasoning. 

276
00:20:36,266 --> 00:20:38,472
So you can do that. 
It's a trick. 

277
00:20:38,472 --> 00:20:43,849
It makes that argument valid but it 
doesn't achieve our goal because our goal 

278
00:20:43,849 --> 00:20:49,295
is not just to make the argument valid, 
it's to make the argument valid so that 

279
00:20:49,295 --> 00:20:52,660
we can understand the pathway of 
reasoning. 

280
00:20:52,660 --> 00:21:00,220
So it's important to know that trick, but 
don't use it unless you have to. 

281
00:21:00,220 --> 00:21:04,176
The examples so far have been pretty 
trivial, I admit it. 

282
00:21:04,176 --> 00:21:08,981
But the same points apply in very 
important context such as politic 

283
00:21:08,981 --> 00:21:13,927
debates, politician can suppress premises 
in perfectly legitimate ways. 

284
00:21:13,927 --> 00:21:19,508
They're just trying to save time and make 
their arguments more efficient, maybe 

285
00:21:19,508 --> 00:21:25,300
even sometimes clearer because you don't 
have to add all those little details. 

286
00:21:25,300 --> 00:21:29,398
But sometimes politicians abuse 
suppressed premises. 

287
00:21:29,398 --> 00:21:34,994
They take things for granted that they 
shouldn't be taking for granted. 

288
00:21:34,994 --> 00:21:39,566
Here's an example. 
A politician might argue, my opponent is 

289
00:21:39,566 --> 00:21:44,300
soft on crime because he's opposed to the 
death penalty. 

290
00:21:44,300 --> 00:21:50,016
Well, that assumes, as a suppressed 
premise, that anyone who's opposed to the 

291
00:21:50,016 --> 00:21:55,611
death penalty must be soft on crime. 
And if the politician were to come out 

292
00:21:55,611 --> 00:21:58,735
and say that, it would seem pretty 
questionable, 

293
00:21:58,735 --> 00:22:04,548
and that's probably why he suppresses it. 
And then another politician might say, my 

294
00:22:04,548 --> 00:22:07,446
opponent is in favor of the death 
penalty, 

295
00:22:07,446 --> 00:22:13,034
so he must not have read all the recent 
studies that show that the death penalty 

296
00:22:13,034 --> 00:22:17,354
doesn't deter. 
Well that argument assumes the suppressed 

297
00:22:17,354 --> 00:22:21,411
premise that if you've read those studies 
you'ld be convinced by them, 

298
00:22:21,411 --> 00:22:25,527
and that the only point of the death 
penalty is deterrence. 

299
00:22:25,527 --> 00:22:31,149
But the point is that politicians talking 
about extremely important issues can take 

300
00:22:31,149 --> 00:22:35,496
things for granted, that if they were 
brought into the light of day will be 

301
00:22:35,496 --> 00:22:37,989
questionable, 
and that's why they hide them. 

302
00:22:37,989 --> 00:22:42,510
So when you're listening to people give 
arguments on important issues in your 

303
00:22:42,510 --> 00:22:45,834
life, 
then you ought to be looking for these 

304
00:22:45,834 --> 00:22:51,903
suppressed premises and asking yourself 
whether or not you really ought to be 

305
00:22:51,903 --> 00:22:57,816
agreeing with them about that assumption. 
Finally, we finished reconstruction. 

306
00:22:57,816 --> 00:22:59,994
Yipee, right? 
Oh, no, not quite, 

307
00:22:59,994 --> 00:23:05,130
because there's one more stage, 
and that stage is drawing a conclusion. 

308
00:23:05,130 --> 00:23:10,325
Of course, if we've come up with a sound 
reconstruction, then we know that the 

309
00:23:10,325 --> 00:23:14,238
argument is sound, 
and we know that the conclusion is true, 

310
00:23:14,238 --> 00:23:18,560
because every sound argument has a true 
conclusion. 

311
00:23:18,560 --> 00:23:23,197
But if we don't come up with a sound 
reconstruction, then what do we say? 

312
00:23:23,197 --> 00:23:25,581
Well, you've got to ask, whose fault is 
it? 

313
00:23:25,581 --> 00:23:30,541
It might be the fault of the argument. 
Maybe we couldn't come up with a sound 

314
00:23:30,541 --> 00:23:34,470
reconstruction because there just is no 
sound reconstruction. 

315
00:23:34,470 --> 00:23:39,236
But maybe we couldn't come up with a 
sound reconstruction because we just 

316
00:23:39,236 --> 00:23:42,200
weren't imaginative enough, or try hard 
enough. 

317
00:23:42,200 --> 00:23:47,263
Still, if we try really long an hard, 
and charitably interpret the argument as 

318
00:23:47,263 --> 00:23:52,590
best we can to make it, look as good as 
we can, and we still can't make it sound. 

319
00:23:52,590 --> 00:23:57,325
Then, we've at least got reason to 
believe that the argument's not sound. 

320
00:23:57,325 --> 00:24:01,205
Of course, that doesn't mean that the 
conclusion's not true, 

321
00:24:01,205 --> 00:24:05,020
because unsound arguments can still have 
true conclusions. 

322
00:24:05,020 --> 00:24:10,353
But at least we know that this argument 
doesn't prove that the conclusion is 

323
00:24:10,353 --> 00:24:13,540
true. 
And so, this method of reconstruction can 

324
00:24:13,540 --> 00:24:18,874
lead us either to the belief that the 
argument is sound, because we found the 

325
00:24:18,874 --> 00:24:22,684
sound reconstruction, 
or to the conclusion is not sound, 

326
00:24:22,684 --> 00:24:28,087
because we tried long and hard to find a 
sound reconstruction that didn't, but 

327
00:24:28,087 --> 00:24:34,000
that's still not going to show us that 
the conclusion of the argument is false. 

328
00:24:34,000 --> 00:24:39,518
The point of reconstruction then is to 
reach a conclusion on this issue of is 

329
00:24:39,518 --> 00:24:44,257
the argument sound or not. 
And if we try our best and do it as well 

330
00:24:44,257 --> 00:24:49,988
as we can and charitably, then we can be 
justified in believing that the argument 

331
00:24:49,988 --> 00:24:51,120
is sound or not.