Meteorite explosions in the Earths atmosphere as large as the one that

Meteorite explosions in the Earth's atmosphere as large as the one that destroyed forests in Siberia, with approximately the force of a twelve-megaton nuclear blast, occur about once a century.

The statement says that meteorite explosions of a particular size in the Earth’s atmosphere occur about once a century.

Of what size?

As large as the one that destroyed forests in Siberia. The explosion had a force of a 12-megaton nuclear blast.

Such large meteorite explosions occur about once a century.

The response of highly automated systems controlled by complex computer programs to unexpected circumstances is unpredictable.

The response of particular systems to unexpected circumstances is not predictable.

Which particular systems are we talking about?

Highly automated systems controlled by complex computer programs.

The response of these systems to circumstances that are not expected is not predictable.

What about the response of other systems to unexpected circumstances?

We aren’t given any information.

A mistake many people may make

As we read the second statement (talking about unexpected circumstances) after the first statement (talking about an event that occurs very rarely i.e., once a century), I believe many people will assume that the rare event would be unexpected.

Can we say that?

No.

Rather, it is entirely possible that since we know that this event occurs about once a century, it is an expected event for the system, i.e., the system designers could have already fed this event into the programming of the system.



Which of the following conclusions can most properly be drawn, if the statements above are true, about a highly automated nuclear-missile defense system controlled by a complex computer program?

The question stem says, “if the statements are true”, so the statements in the passage are FACTS for us.

We need to find an option that states a conclusion that can most properly be drawn from the facts in the passage - the conclusion about the kind of system the second statement talks about i.e. a highly automated nuclear-missile defense system controlled by a complex computer program.



(A) Within a century after its construction, the system would react inappropriately and might accidentally start a nuclear war.

Incorrect. - This option is wrong for two reasons:

We don’t know that the once in a century event is an unexpected event for the system. If it’s an expected event for the system, we have been given no information about how the system would respond to such an event.
We are given that the system reacts in an unpredictable way to unexpected events. We’re not given that the response is “inappropriate”; the response could be entirely appropriate.

(B) The system would be destroyed if an explosion of a large meteorite occurred in the Earth's atmosphere.

Incorrect. - We have been given ZERO information about what it takes to destroy such a system.

Some of you may be wondering, “what if the whole Earth is destroyed?”

In such a case, assuming that the system was installed on Earth, we can say that the system will be destroyed.

However, we’re not given that explosion of a large meteorite will destroy the whole Earth. So, we cannot infer this option.

(C) It would be impossible for the system to distinguish the explosion of a large meteorite from the explosion of a nuclear weapon.

Incorrect. - This option is popular. My hypothesis is that people who mark this option or consider this option to be a good contender make three mistakes:

• Assume that once in a century event is unexpected for the system
• Fail to see the difference between the ideas
  
  • that the response is unpredictable
  • that the system WILL NOT be able to distinguish between two events
• Assume that the system can only differentiate between explosions based on the quantum of force

We know that the response of the system will be unpredictable in case of unexpected situations. However, “unpredictable” means something that cannot be predicted; the response could very well be very appropriate to the situation, and the system could very well distinguish between the meteorite explosion and the explosion of a nuclear weapon? How can we be sure that the system WILL NOT be able to distinguish between the two explosions? We cannot be.

(D) Whether the system would respond inappropriately to the explosion of a large meteorite would depend on the location of the blast.

Incorrect. - This option is wrong for three reasons:

1. We don’t know that the once in a century event is an unexpected event for the system. If it’s an expected event for the system, we have been given no information about how the system would respond to such an event.
2. We are given that the system reacts in an unpredictable way to unexpected events. We’re not given that the response is “inappropriate”; the response could be entirely appropriate.
3. We’ve been given no information to suggest that the response of the system or the unexpectedness of the situation depends on the location of the blast.

(E) It is not certain what the system's response to the explosion of a large meteorite would be, if its designers did not plan for such a contingency.

Correct. - “Not certain” means “not predictable”.

The “if” part makes the statement pertain to a situation that is unexpected for the system (the system designers did not plan for such an event -> means that the event is going to be unexpected for the system)

The statement means that one cannot predict the system’s response to the explosion of a large meteorite if the explosion is unexpected for the system.

We can infer this option from the second statement of the passage.