Important!
A new specification for Critical Thinking was introduced for first teaching in 2008 / 2009. Although the new course covers similar ground to the old, changes have been made, particularly to the structure of the AS units. The most significant change is that some content that was previously only in Unit 2 is now also in Unit 1, but please see OCR's guide to the changes for more detail.
This website remains available in the hope that its contents will still be useful, but if you choose to use it you must bear in mind that it no longer reflects the most recent version of the A-level Critical Thinking course.
Weak Analogy
Arguments by analogy rest on a comparison between two cases. They examine a known case, and extend their findings there to an unknown case. Thus we might reason that because we find it difficult to forgive a girlfriend or boyfriend who cheated on us (a known case), it must be extremely difficult for someone to forgive a spouse who has had an affair (an unknown case).
This kind of argument relies on the cases compared being similar. The argument is only as strong as that comparison. If the two cases are dissimilar in important respects, then the argument commits the weak analogy fallacy.
Links
Case Study