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Tutorial 6 - Macrostructure

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Pyramid Rule 1

The first aspect of the Pyramid Rule is that higher in the argument tree a reason or objection appears, the more general or abstract it should be.

Primary considerations should be the most general or abstract considerations bearing upon the main contention.

 
Discussion

Examples:

In this example from Tutorial 4, the objection at level 1 is a more general claim than the reason which supports it at level 2.

Similarly, in this argument the objection is a general objection to the Moon landing; the supporting reason is a more specific piece of evidence supporting the general objection.  There might also be other reasons to think that The astronauts cannot have been to the Moon.

 
New Concepts

The Pyramid Rule: More general or abstract considerations should appear higher in the argument tree, and considerations at the same level of the tree should be at roughly the same level of generality or abstraction. 

Pyramid Rule 2

The second aspect of the Pyramid Rule is that reasons or objections at a given level in the tree should be at roughly the same level of generality or abstraction.

 
Discussion

Example

When the level problem above is fixed, the argument map looks like this

Note that the objection has become a reason when it moves down to support another primary objection.

The lower the level, the more difficult it is to ensure that a complex argument tree observes this aspect of the Pyramid Rule.  Fortunately, the lower the level, the less important this principle is. The upper levels of an argument tree determine its overall structure, and getting things right at those upper levels helps ensure that it is constructed solidly, even if it is a bit messy on the periphery.

 
New Concepts

The Pyramid Rule: More general or abstract considerations should appear higher in the argument tree, and considerations at the same level of the tree should be at roughly the same level of generality or abstraction. 

Pyramid Rule - Structure

An argument map observing both aspects of the Pyramid Rule should end up looking a bit like a pyramid.

 
Discussion

It is rare for an argument map to take on a perfect pyramidal shape.  Some branches of the argument tend to be wider or longer than others.  Nevertheless you should keep the pyramid image in mind because it is the ideal to which maps of real arguments approximate when they have a proper macrostructure.

Groups

To state the next macrostructure rule (MECE), we need the simple concept of a group of reasons or objections.  This is simply all reasons and objections bearing directly upon the main contention or any other reason or objection.

 
Discussion
 
New Concepts

A group of considerations is all reasons and objections bearing directly upon the main contention or any other reason or objection.

MECE - Mutually Exclusive

The first aspect of the MECE rule is that within any group, the reasons and objections should be mutually exclusive - that is, they should be genuinely distinct from each other.

 
Discussion
   
Because the two objections make basically the same point, you don't need both of them on the map.  If you get rid of the second objection (Nasa faked the evidence) then the reason for it is added to the reasons for the first objection.

This is what the above argument map looks like after corrections have been made:

The "mutually exclusive" rule does not mean that there can never be any conceptual overlap within a group.  Sometimes terms or concepts may appear in more than one reason or objection.  In fact, given that the Rabbit Rule should be observed with regard to each and every reason and objection in the group, there should be some conceptual overlap.  

It does mean that reasons and objections should be genuinely distinct from each other, even if they have some concepts in common. Informally, they should not be making the same point, wholly or even partially. 

It can be quite difficult to spot when considerations are not mutually exclusive.  It is particularly hard to notice when there are also level problems, i.e., the Pyramid rule has not been properly observed. For example

Superficially, the two objections here are really quite different; that is, they appear to be mutually exclusive.  Notice however that there is a level problem; the two objections violate the second part of the Pyramid Rule, which says that considerations at the same level should be at roughly the same level of generality or abstraction.  The second objection belongs at a lower level. 

Once the level problem is fixed, the similarity between the two objections becomes more apparent.  They are not mutually exclusive; the second objection is really part of the evidence for the first one.

 
New Concepts

Mutually exclusive (ME): Within a group, considerations should be genuinely distinct from each other. ME is the first aspect of the MECE rule.

The MECE Rule: Considerations in a group should be mutually exclusive (no overlaps) and collectively exhaustive (no gaps).

MECE - Collectively Exhaustive

The second aspect of the MECE rule is the "CE" part: that within any group, the reasons and objections should be Collectively
Exhaustive
- that is, between them, they should cover all the arguments relevant at that point.

 
Discussion

Example

On p.9 of Apollo Moon Landings, the author asks "What evidence is there that the Apollo Moon landings actually took place?"

Three separate issues are considered; Moon rocks, telescope photos, and "Occam's Razor."  If you look closely at the discussion of telescope photos, you'll see that it does not actually present evidence that the Apollo Moon landings took place; rather, it explains why a certain category of possible evidence is not available.  So really only two arguments are raised:

Note that the Occam's Razor reason needs further elaboration; only the first premise has been provided here, and the co-premises are needed for the reason to make sense.)

The important issue here is whether the argument is Collectively Exhaustive - that is, whether the group of considerations currently listed as bearing on the main contention.

Even if you consider only the supporting evidence (i.e., ignoring all the objections for the moment), the argument is not collectively exhaustive.  There are other reasons to believe that the Apollo astronauts landed on the Moon.

For example, one very general kind of argument that the Apollo astronauts landed on the Moon goes along these lines: landing on the Moon was an enormously important political goal, and the U.S. had the technical capacity to achieve it.  Thus, it is likely that the Apollo astronauts did in fact land on the Moon.

When this reason is added, the argument map looks like this:

This reason may be somewhat controversial, but a complete argument map considers all arguments, not only the ones deemed to be good by a particular observer.

You may want to consider if there are any other arguments, at this level, which should be added:

ALL the arguments

"Collectively exhaustive" means that the group covers ALL the arguments.  It is an interesting question what all means here. Roughly, it means all relevant, serious arguments.  These include:

There is no need to put on the map considerations which are obviously completely irrelevant or absurd.

 
New Concepts

Collectively exhaustive (CE): Within a group, considerations should cover all the relevant, serious arguments; they should leave no gaps. CE is the second aspect of the MECE rule.

The MECE Rule: Considerations in a group should be mutually exclusive (no overlaps) and collectively exhaustive (no gaps).

Debates

A debate is a multi-level dispute, i.e., an argument structure in which there are both reasons and objections to a single claim, and where the reasons and objections are themselves disputed. 

 
These first-layer reasons and objections ("pros and cons") make the argument structure a dispute.
These second-layer reasons and objections make the argument structure a genuine debate.  

This diagram illustrates the simplest possible argument structure which would count as a debate in the current sense.

 
Discussion

In ordinary conversation, the term debate is often used quite loosely to refer to just about any argumentative disagreement. Here, we are giving it a more precise technical definition.  It is an argument structure of a certain sort. 

A debate in this sense is, roughly, where each side actually responds to the (top level) moves made by the other side.  It is not enough for you to provide your reasons to accept the conclusion and for me to provide my objections to it.  Rather, I must actually respond to your reasons - and you must respond to my objections.  In other words, in a genuine debate, each side takes the other side's arguments seriously, not just their position. 

The concept of a debate is important because, all too often, people concentrate on mounting their own arguments, and fail to challenge what the other side says, even if the other side has very powerful arguments.

For example, the Hoax Believers tend to focus all their attention on their own arguments that the Moon landings were a hoax, and neglect the powerful arguments that the Apollo Moon landings really happened.

 
New Concepts

A debate is a dispute in which the first-level reasons and objections are themselves disputed.

Summary

 
Key Points

 
New Concepts

The Pyramid Rule: More general or abstract considerations should appear higher in the argument tree, and considerations at the same level of the tree should be at roughly the same level of generality or abstraction. 

A group of considerations is all reasons and objections bearing directly upon the main contention or any other reason or objection.

The MECE Rule: Considerations in a group should be mutually exclusive (no overlaps) and collectively exhaustive (no gaps).

Mutually exclusive (ME): Within a group, considerations should be genuinely distinct from each other. ME is the first aspect of the MECE rule.

Collectively exhaustive (CE): Within a group, considerations should cover all the relevant, serious arguments; they should leave no gaps. CE is the second aspect of the MECE rule.

A debate is a dispute in which the first-level reasons and objections are themselves disputed.

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Copyright Austhink 2003-2006

 Last updated 28-Aug-2007