--  作者：mike1999
--  发布时间：2003-6-9 13:22:00

--  A course for a critical thinker!![分享] 第一课
从今天开始我将把握每天学习的course的精华部分贴上来。希望大家一起学习！
第一课Introduction to Statements (or Claims)
Sentences that can be true or false--the vast majority of all sentences in critical thinking--are called statements or claims. Note that you don\'t need to know whether a statement is true or false, just that it has the form of sentence that can be true or false. We may never know the truth of such sentences as "Before he died, Elvis was thinking of becoming a vegetarian" or "The universe is younger than its oldest galaxies"; we may not even completely understand them. But as long as they have the possibility of being true or false, such sentences are statements.

We can further categorize statements by three qualities:

whether they are verifiable, evaluative, or advocatory claims;
whether they are specific or, if non-specific, whether the qualification strengthens or weakens the claim;
whether they serve as conclusions, premises, or support in an argument.
In this section, we will be focusing on the first two qualities only.
              Qualified and Specific Statements
Specific claims contain or imply language or figures of an exact nature:

45% of the people surveyed supported the reforms.

One-third of the investment has been lost.

This marked the first time that India successfully orbited a satellite.

In those three sentence, "45%," "one-third," and "first" represent specific information. Such statistical statements are powerful and persuasive expressions in an argument, but they are also easy to attack, because a single example to the contrary is sufficient to refute them. The most common specific statements are universal ones, in which the figure involved is either "100%" or "0%," usually expressed by words such as always, never, all, none, everyone, no one, and so on.
Non-specific claims are ones in which no specific number is cited; as a result, they are often more difficult to attack. Consider the following examples:

49% of those casting ballots voted for Kennedy.
Approximately 49% of those casting ballots voted for Kennedy.
More than 49% of those casting ballots voted for Kennedy.
Less than half of those casting ballots voted for Kennedy.
Kennedy received more votes than did Nixon.
Only the first example above is a specific claim. The second qualifies that specific claim with the word "approximately," making the statement weaker but harder to disprove. The last three examples are all comparative statements, a type of qualification that operates by comparing the subject of the statement with something else (49% of the votes vs. "more than 49%," half the votes vs. "less than half," the votes for Kennedy vs. the votes for Nixon). Comparative and other non-specific claims are usually harder to disprove than specific claims, but not always; often, they are also more effective in an argument.

A claim with a modifier is considered qualified whether it is specific or non-specific. Non-qualified claims have no modifiers at all: "The investment has been lost" or "Kennedy received votes." These sound universal, but may not be.