What fallacy is represented below?
The death penalty is a warning just like a lighthouse throwing its beams out to sea. We hear about shipwrecks, but we do not hear about the ships that the lighthouse guides safely on their way. We do not have proof of the number of ships it saves, but we do not tear the lighthouse down.
There are probably two fallacies here. There is a fallacious argument by analogy and also an appeal to ignorance.
First there is the bad analogy: the death penalty is being compared to a lighthouse. The comparison is that both send warning signals and so are valuable. However, the comparison continues, we don't know who receives and responds to those warnings. Ships that see the lighthouse and so avoid crashing don't make it into the news; only those that do crash. Similarly, it is being argued, the death penalty warns people not to committ murder--and we don't know how many people receive this warning and decide not to murder. ...
Exposes and explains the fallacious reasoning involved in comparing the death penalty to a lighthouse (warning signal).