People believe the common sense is common to everyone. And people believe what they see is what it is. But if you are a software designer, you fill face a large difficulty or hard challenge if you don't doubt about what customer say. Sometimes common sense is very hazardous. This presentation explains why the common sense is hazardous. And this slides give you the hint to avoid the tragedy in software development.

1. 5 April 2016 (C) 2016 Yuichi MORIWAKI 1
Hazardousness of common sense
Yuichi MORIWAKI

2. 5 April 2016 (C) 2016 Yuichi MORIWAKI 2
Common Sense
• People believes that the meaning of common sense is the same recognition of things. For
example the same value, the same meanings and the same context. Even we can understand that
the common sense may be very different from US and China, but if we are too much involved in a
same society for long, it may be difficult to be aware of the difference in common sense exactly
exists.
• For example, here is a figure as below,
• Every one, you and the people around you believe that this shape is “triangle”. It is obviously a
triangle.
• But some one from different place says this is a circle. You and your friend may tease the person
as he said that the shape is a circle. He never admits that he is wrong. Why he doesn’t? We can
ignore him as if he is bothering other people by saying that this shape is circle. But if you are
smart enough, you can consider this shape may be circle from his point of view.

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Common Sense
• Circle? How?
?

4. 5 April 2016 (C) 2016 Yuichi MORIWAKI 4
Common Sense
If this object is conical in shape.

5. 5 April 2016 (C) 2016 Yuichi MORIWAKI 5
Common Sense
People who watch the shape only from its side.
The shape will be a triangle.

6. 5 April 2016 (C) 2016 Yuichi MORIWAKI 6
Common Sense
People who watch the shape only from its
top.
The shape will be a circle.

7. 5 April 2016 (C) 2016 Yuichi MORIWAKI 7
Common Sense
• What makes the difference? And why we can’t be aware of it?
The difference is from the point of view. If the view point is different, the shape may be
different. If we find some different opinion, we need to consider that the person who has
different opinion may has different point of view. And you may ask the person about the
view point.
And the reason why we are not aware of it is as we always process most of our thoughts
and recognition based on our common sense. As far as we are successful in a certain
business field, we lose the existence of different view point.
We sometimes need to doubt about our view point.

8. 5 April 2016 (C) 2016 Yuichi MORIWAKI 8
Common Sense
In a software specification definition process, we always do customer interview to know the
true requirement or demand of customer. But we need to be very careful when we are
hearing about customers voice. They only have their view point. What they believe and
what they see may be different from what we see.
• To avoid this kind of misrecognition of things, software designer first need to draw a
picture of what he heard and confirm if it is exactly what customer see. And reconfirm
by explaining the picture from other view point.
If we don’t share the correct shape,
the software wont work properly.
The system may not bring any
benefit to customer.
Do not understate the confirmation
process especially during
specification definition.