In terms of Artificial Intelligent and Logic Knowledge, What is the difference between sound and unsound reasoning?
Also, what kind of search Does ID3 algorithm use? Is it Breadth-first search?
Thanks
+1
A:
Reasoning is sound if the premises are true and the conclusion can be drawn from just those premises. For example:
An answer upvote gets you 10 rep
Jack has 4 answer upvotes
Jack has 40 rep
is sound (ignoring other rep factors :) ). If it read:
An answer upvote gets you 50 rep
Jack has 4 answer upvotes
Jack has 200 rep
the reasoning would be valid, but not sound, because one of the premises is false
Michael Mrozek
2010-05-02 23:29:31
Maybe I'm being dense, but I don't see how the logical implication has changed between these two examples here?
Kylotan
2010-05-04 14:53:35
It hasn't; both arguments are *valid*, which means the conclusions follow from the premises. For an argument to be *sound*, it needs to be valid and have all true premises, which the latter doesn't
Michael Mrozek
2010-05-04 14:59:02
Sorry, I am still confused. Can you make another more explicit example please? Thanks
leon
2010-05-04 21:16:36
+1 correct, though it's not the whole story; I put a bit more in my answer. But with respect to the important question of the premises to your example, who is Jack? Might he have more than 4 upvotes by now?
Charles Stewart
2010-05-05 09:21:06
@leon I don't know if this is clearer, but: "The chair is made of wood. All wooden things are painted blue. Thus, the chair is painted blue" is valid reasoning (if you assume it's true that the chair is made of wood and that all wooden things are painted blue, you can logically conclude that the chair is painted blue), but unsound, because it's not true that all wooden things are painted blue -- one of the premises was wrong
Michael Mrozek
2010-05-05 10:00:39
A:
Charles Stewart
2010-05-05 09:16:55
A:
A logic consists of a set of proposition and inference rules on these.
Given a logic L every proposition p that can be derived by the successive application of inference rules is said to be sound.
Any proposition p that cannot be derived can be said to be unsound, but no one says that. We just say that it is not in L.
A logic L is complete if every statement p that you (as an intelligent human) think should be true is sound.
Thus, we seek sound and complete logics.
This question sounds like a homework question for AI 101.
Jose M Vidal
2010-05-06 15:18:56