hello everyone mason from magoosh here i want to talk to you today about a gmat question type that
maybe you haven't thought much about the question type i have in mind is called the find the
assumption question type which is a very common subcategory of the critical reasoning section on
the gmat now i know what you're thinking mason you do gre stuff what are you doing in a gmat video
well i do know a little bit about the gmat and quite a bit more about assumptions having gotten
my bachelor's and master's degree in philosophy so follow me a ways down this gmat rabbit hole
and we'll see if we can get to the bottom of these assumption questions the key to doing well
on assumption questions is first understanding the role that assumptions play in an argument
now arguments are of course extremely diverse however the gmat is a standardized test so the
arguments that you're going to see in the gmat are relatively formulaic the typical gmat argument
has three parts to it we have the premise the assumption and the conclusion the premise is sort
of the logical starting point it's just taken to be agreed upon that this premise is a fact
the conclusion is the point that the author is trying to drive the reader towards in the argument
and the assumption is the link that brings those two things together now even though
the assumption is not stated explicitly in the argument it actually is the cornerstone to the
whole argument hanging together think about the assumption like a logical bridge that gets
you from the premise to the conclusion so if the premise comprises a and the conclusion comprises b
the assumption is what brings these two pieces together here's a quick and simple example
michaela likes the movie legally blonde edward will like the movie legally blonde now what is the
assumption that brings those two things together well that edward likes the same kind of movies
that michaela likes here's a big idea we can only safely draw the conclusion from the premise
if we trust the assumption between them right that bridge has to hold up between those two things
otherwise they just don't go together so if a statement does not relate the information in
the premise directly to the conclusion then it's not an assumption when identifying the assumption
on these questions it's important to keep in mind that assumptions tend to be more general
and less specific so for example let's say our premise is sean has quality x and our
conclusion is sean has quality y now what's the assumption that links these two things together
well we're not going to talk about sean here we're going to talk about the qualities x and
y so we might say something like anyone who has the quality x also has the quality y so what we've
taken is a general information that links these two things together but we've omitted the specific
name or person involved now another tactic for identifying the assumption is to first identify
the premise and the conclusion right it's kind of hard to know where to find the bridge if we don't
know where it's starting and where it's ending so identify the premise and the conclusion first
and then isolate the assumption another incredibly helpful tactic for identifying the
assumption is what's called the negation test now that sounds really sophisticated and complicated
it's actually very simple let's return to that example with michaela and edward about the movies
so if the assumption is that edward is going to like the same movies that michaela likes
if that assumption doesn't hold true if it's not actually correct then what happens to the
entire argument well of course it falls apart the argument's no longer valid it wouldn't be
reasonable for us to draw that conclusion that edward's going to like the movie legally blonde
if the assumption is not true that edward and michaela like the exact same movies
so this is called the negation test and it's just a question of what happens if this thing isn't
true how does that bear on the argument as a whole does that bridge stand or does it collapse so when
you're working through assumption questions what you should do is go through each answer choice
and run that negation test so for each one ask well if this is not true what happens to the
argument if the argument falls apart completely if that assumption is not true then you've located
your assumption no more work needs to be done if however you negate one of the statements and the
conclusion is still plausible then that's probably not the correct answer the assumption has to be
completely critical to the argument being valid or not valid there are a few caveats to keep in mind
while running this negation test we have to be sure that we're negating correctly what do i mean
so let's take this statement all bats are nocturnal as an example how would we go about
negating this statement well you might think that's not that hard let's just say not all
bats are nocturnal but we have to be careful here think about what not all implies that implies that
some bats might be nocturnal maybe even most bats are nocturnal but there are a few that are not
and that's not quite the same thing as negating that statement completely
what we want to do there we'd want to probably say that no bats are nocturnal that would be a
proper way to negate that statement because that doesn't leave any wiggle room at all
for there being some or even most bats being nocturnal this is important because if we run
a test and we do the negation incorrectly we could run into a situation where because some bats might
be nocturnal this doesn't actually completely make the argument fall apart in the same way that
no bats are nocturnal could completely dismantle it so make sure you're being careful when you run
your negation tests and ask am i truly negating this statement or am i just partially doing
so let's do a quick recap what did we cover in today's video we talked about the three parts of
gmat arguments the premise the assumption and the conclusion we talked about the assumptions being
the cornerstone of arguments they are the bridges that link premises to conclusions and without them
the argument falls apart then we talked about the negation tactic where we go through and negate
each statement we see what happens to the argument and if the argument collapses then we know we have
our assumption identified all right my friends we did it we went down that rabbit hole we got
to the bottom of assumption questions if you still have questions about these drop a comment below
reach out to us at helpingmagoosh.com or pop onto the magoosh blog where we have tons of resources
to help you go further and further down those rabbit holes and improve your score today