# GMAT逻辑入门（一）Arguments

来源：Chasedream.com    要点：GMAT逻辑入门

What is an argument?

An argument in logic is a set of one or more meaningful declarative sentences (or "propositions") known as the premises with another sentence known as the conclusion. Therefore, each argument has at least two components: 1) a piece of evidence or proposition, officially called a “premise,” and 2) a conclusion.

Consider the following two statements:
1)Ming Li is smart.
2)Ming Li went to Peking University.

Each statement by itself is simply a claim or an assertion. Can you combine them together to form an argument?

One answer might be:

Ming Li is smart because he went to Peking University.

The red part of the answer is the conclusion; the blue part of the answer is the premise. These color codes will be the convention I use to label premise and conclusion through out the series.

A premise supports a conclusion. Most argument are not bullet-proof. That is: the evidence provided does not PROVE the conclusion reached beyond a shadow of a doubt. A premise is just an evidence, one reason to shed some positive light on the conclusion, one piece of information which makes the conclusion more likely. In CR, all premises given in the stimulus are considered true. In the above example, we should not doubt whether Ming went to Peking University or not. However, we can analyze the argument by focusing on the logic which connects the premise and the conclusion in an argument.

Indicators

How to tell which statement is a premise or a conclusion in an argument? A quick way is to find indicators such as because, since, for, as, considering, whereas, and on the grounds that, which signal to the reader that a premise is coming! In the example above, Ming Li is smart because he went to Peking University, he went to Peking University is the premise since this statement follows the word because.

A second way to form an argument using exactly the same statements is:

Because Ming Li is smart, he went to Peking University.

This is a totally different argument from the first one in that the premise and the conclusion switch their places. Ming Li is smart is now the premise.

These two examples show that the order, in which each statement shows up in an argument, is less important than the logical relationship shown in the argument when deciphering which is the premise and which is the conclusion. Use the indicators to help you march through the puzzle in the beginning. The indicators for a conclusion might include: thus, therefore, accordingly, hence, in this way, consequently, and as a result.

What if there is no indicator in the argument?

In case you cannot find an indicator for premise/conclusion, you have to understand what the aruthor is trying to say and ask yourself which part is the conclusion and which part is the premise to support the conclusion. Consider the following example:

Every milk product from Three Deers must be recalled. These products contain melamine which could lead to renal failure.

Which one is the conclusion? Which one is the premise? Most likely you would say that the 1st sentence is the conclusion and the 2nd sentence is the premise.
Every milk product from Three Deers must be recalled. These products contain melamine which could lead to renal failure.

If in doubt, 1) simply connect the two sentences using the word because; and 2) see which one of the resulting arguments makes more sense:
1) Every milk product from Three Deers must be recalled because these products contain melamine which could lead to renal failure.
2) Becasue every milk product from Three Deers must be recalled, these products contain melamine which could lead to renal failure.

In CR test, if you can locate the premise and the conclusion of an argument, you have 50% chance of getting the right answer in the end. Train your eyes and brains to identify the conclusion of an argument quickly and precisely. Make sure your first step of a long march to the victory gets off on the right foot.