Necessary/Sufficient 2

Necessary is something that must occur for the second act to follow (but does not guarantee that Act 2 will occur).

For example, it is necessary to put food into your mouth before you can eat. You can't eat without first putting food into your mouth.

So in general, when you have a statement that expresses a necessary condition, it allows you to infer something in just two cases:

1. You can infer from knowing that if the necessary condition is not met that the thing it is the necessary condition for does not occur.

- If you don't buy a Powerball ticket, then you won't win the Powerball jackpot.

2. You can infer that the necessary condition is met from knowing that the thing it is the necessary condition for occurs.

- If you won the Powerball jackpot, then it means you bought a Powerball ticket.

Sufficient is something that guarantees that the second act follows.

Rain is sufficient to make the sidewalk wet.

If the sidewalk is dry then you know it didn't rain.

So in general, when you have a statement that expresses a sufficient condition, it allows you to infer something in just two cases:

1. If you know that the sufficient condition is met, then you can infer that the thing it is the sufficient condition for occurs

2. You can infer that the sufficient condition is not met from knowing that the thing it is the sufficient condition for does not occur

Necessary and Sufficient Conditions

Necessary Conditions:
If P is necessary for Q, then Q cannot be true unless P is true.

In other words:
Q is true only if P is true.
"P is necessary for Q because P being true is needed for Q to be true."

For example, what is necessary to get into a university.

1. You must be a human being (a bug can't get into a university)
2. You must submit an application (without an application, you can't get in)
3. Having decent grades (if you're a dummy then you won't get in)

Another example, what is necessary to win the Powerball

1. You must buy a ticket (without a ticket you can't win because you have no chance)

Necessary conditions represent things that must be in place for a certain outcome to occur but in and of itself does not guarantee that certain outcome. If that desired outcome occurs, however, the necessary condition was first met.


Sufficient Conditions:
If P is sufficient for Q, then P's being true is enough to make Q true.

In other words:
If P is true then Q is true.
"P is sufficient for Q because is P is all you need to get Q, P is enough to get Q."

For example, what is a sufficient condition to get into a university.

1. You are a super smart whiz kid who won the Nobel Peace Prize (the university wants you then)
2. You are the No. 1 athlete in the world (the university wants you then)

Another example, what is sufficient to have make the sidewalks get wet?

Rain - if it rains then it guarantees that the sidewalk will get wet. Of course there are other things that can cause the sidewalk to get wet (sprinkler system, water balloon, etc.) but just as long as there is rain that's enough to say that the sidewalk is going to get wet.


Something that is Necessary but not Sufficient: Steering a Car Well
1. Steering a car well is necessary for driving a car well. However, it is not sufficient for driving well. What if you steer like a boss but drive through a stop sign without obeying it?

Something that is Sufficient but not Necessary: Boiling a Potato
1. Boiling a potato is sufficient for cooking it. However, it is not necessary for cooking it as there are other ways in which you can cook a potato (microwave it, bake it in the oven, etc.)

Identifying Points on Which Disputants Hold Conflicting Views

This is a famous painting. Do you know what it is?

Mary: Computers will make more information available to ordinary people than was ever available before, thus making it easier for them to acquire knowledge without consulting experts.

Joyce: As more knowledge became available in previous centuries, the need for specialists to synthesize and explain it to nonspecialists increased. So computers will probably create a greater dependency on experts.

What do Mary and Joyce disagree about?

Step 1: Form a clear mental picture about what's going on.
Step 2: What does what each person say commit them to?

So Mary says "Computers will decrease our dependency on experts."

Joyce says "Computers will increase our dependency on experts."

Correct answer: M & J disagree over whether computers will increase the need for ordinary people seeking knowledge to turn to experts. Mary says no. Joyce says yes.

Some points to consider:
1. The evidence that two speakers disagree about a particular point ALWAYS comes from what they EXPLICITLY say.
2. Rely only on what a speaker explicitly says and on what can be properly inferred from that.
3. The incorrect answer choices are 1. two speakers agree or 2. the view of at least one of the speakers cannot be determined on what has been said.

What Can Be Concluded (MBT and Soft MBT)

What is supported by the body of available evidence? A and B conclusively lead to what?

You are looking for something that is guaranteed to be true by the information you have been given. In other words, something that MUST BE TRUE.

Example:

Any sale item that is purchased can be returned for store credit but not for a refund of the purchase price. Every home appliance and every piece of gardening equipment is on sale with selected construction tools.

Answer:

Home appliance, gardening equipment and the selected construction tools cannot be returned for cash. Store credit only. No piece of gardening equipment is returnable for a refund.

Some points to consider:

1. For some claim to logically follow from certain information, that information has to guarantee that the claim is true. It isn't enough for the information to strongly support the claim; it has to consluviely establish the claim.

2. Answer choices are often incorrect because they take things one step beyond what the evidence supports. The claim might be too sweeping, they might say "all" when the evidence supports only a "most". Or where a statement about "likely to be" is warranted, an incorrect answer choice might say "is". Or where a statement about "all known cases" is warranted, an incorrect answer choice might say "all cases."

3. A modest or limited claim can be a correct answer even if the information supports a stronger claim. For example, there will be a festival every month and there will be a festival in June are equal statements.

4. Incorrect answers to questions about what logically follows can be claims that receive some support but that nevertheless could be false even though all of the information is correct.

Soft Must Be True
Some questions ask you to identify a position that is supported by a body of evidence but not supported conclusively.

You generally get some information rather than an argument. Choose the answer that receives strong support for the information you're provided with and eliminate the answer choices that receive no significant support (the incorrect answer choices).

An example

People should avoid taking the antacid calcium carbonate in doses larger than half a gram, for despite its capacity to neutralize stomach acids, calcium carbonate can increase the calcium level in the blood and thus impair kidney function. Moreover, just half a gram of it can stimulate the production of gastrin, a stomach hormone that triggers acid secretion. 

Prediction: Don't use in doses of larger than half a gram. Why? Two reasons: 1. calcium in blood can impair kidney function and 2. gastrin can be created which in turn leads to acid secretion.

Correct answer choice: Half a gram of calcium carbonate can causally contribute to both the secretion and the neutralization of stomach acids.

Some points to consider
1. Base your judgment about whether or not a particular answer choice is supported strictly on the information that is explicitly provided in the passage.

2. Support for the correct answer does not have to involved all of the information provided.

Matching Patterns of Reasoning

1-2-a-1-2-3

How to do tackle these problems?

Get a solid intuitive grasp of the logical structure of the reference argument:

What is the conclusion and how do the premises fit together to support the conclusion?


Some tips
1. Similarity or dissimilarity in subject matter does not matter
2. Background material that is not a premise or conclusion does not matter
3. Order of the premises or conclusion does not matter

An example
Conclusion: Ash is unlikely to ever collect a stone not from Tanzania.
Premise 1: She only collects Tanzanite stones.
Premise 2: All known deposits of Tanzanite are in Tanzania.

Prediction
Conclusion: It is UNLIKELY (not definitely will not happen)

Conclusion: The owls will probably never eat an animal that lives outside the lagoon.
Premise 1: The diet of all the owls on Scrag Island consists entirely of frogs on the island.
Premise 2: The only frogs yet discovered on Scrag Island live in the lagoon.

Main Point

Question: Are eggs a dairy product?



Conclusion: Despite being sold in the dairy aisle, eggs are not a dairy product. 

Premise 1: Dairy is a product of the mammary gland of mammals. 

Premise 2: Dairy refers to milk and anything made from milk, like cheese, butter and yogurt. 

Premise 3: Eggs are not made from milk. They don't even come from a milk-producing animal.

Main Point: Look for a position that the argument as a whole is trying to establish.

If it is not the Main Point, then it is:

1. A statement that, either directly or indirectly, give reasons for that position.
2. Background information
3. Contextual information

50,000 Calories Challenge

I am probably the third guy from the right at the moment. Would like to get to the second guy.

During Q4 2016, I'm going to burn 50,000 calories. As a result, I should lose 10 pounds and drop from 165 to 155 (at a minimum) and hopefully drop to 150.

October 2-9

6765 burned, 43,235 more to go

October 10-16


October 17-23


October 24-30