What's the difference between sound and unsound reasoning?

Question

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

Answer 1

Reasoning is sound if the premises are true and the conclusion can be drawn from just those premises. For example:

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Jack has 4 answer upvotes

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Jack has 40 rep

is sound (ignoring other rep factors :) ). If it read:

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Jack has 4 answer upvotes

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Jack has 200 rep

the reasoning would be valid, but not sound, because one of the premises is false