induction deduction

Deduction归纳: reasoning from general premises, which are known or presumed to be known, to more specific, certain conclusions. Induction演绎:reasoning from specific cases to more general, but uncertain, conclusions.
Deduction:
commonly associated with “formal logic.”
involves reasoning from known premises, or premises presumed to be true, to a certain conclusion.
the conclusions reached are certain, inevitable, inescapable.
It is the form or structure of a deductive argument that determines its validity
the fundamental property of a valid, deductive argument is that if the premises are true, then the conclusion necessarily follows.
The conclusion is said to be “entailed” in, or contained in, the premises Induction
commonly known as “informal logic,” or “everyday argument”
involves drawing uncertain inferences, based on probabalistic reasoning. the conclusions reached are probable, reasonable, plausible, believable. The form or structure of an inductive argument has little to do with its perceived believability or credibility, apart from making the argument seem more clear or more well-organized.
The receiver (or a 3rd party) determines the worth of an inductive argument
Deductive reasoning is either “valid” or “invalid.” A deductive argument can’t be “sort of” valid.
If the reasoning employed in an argument is valid and the argument’s premises are true, then the argument is said to be sound.
Inductive reasoning enjoys a wide range of probability; it can be plausible, possible, reasonable, credible, etc.
The inferences drawn may be placed on a continuum ranging from cogent at one end to fallacious at the other.
问题在于，演绎和归纳并非是根据一般与特殊的关系来定义的。

由特殊到一般的推理完全可能是演绎的，比如“张三在看我的博客，所以有人在看我的博客”，又比如“我的右手能写字，我的左手能写字，所以，我的手能写字。

”同样的道理，由一般到特殊的推理也完全可能是归纳的。

“迄今我知道的乌鸦都是黑色的，所以我即将见到的这只乌鸦是黑色的”。

可见，deduction and induction的区别并不在于“一般与特殊”的关系，而是在于其他方面：关键是看前提的真是否能够完全保障结果的真。

如果是则为deduction, 如果不是完全保障，那么则是induction。