Next to each syllogism below is an interactive Venn diagram template. Toggle between the "shade" and "X" modes as needed, and click the appropriate place on the diagram to alter it. Remember, we only diagram the premises of the argument, not the conclusion. Once you've filled in the diagram, you can check it by clicking the appropriate button below the syllogism. If you make a mistake, you can click the reset button to start over. (An undo button is in the works.) Once the diagram is correct, you'll be asked whether the syllogism is valid or invalid. Check to see if the diagram forces the conclusion to be true. If so, it's valid; otherwise not.
Syllogism 1
No horses are zebras.
Some mares are zebras.
Therefore, some mares are not horses.
Syllogism 2
No eukaryotes are prokaryotes.
Some archaea are prokaryotes.
Therefore, some archaea are not eukaryotes.
Syllogism 3
Some tigers are meat eaters.
Some tigers are striped animals.
Therefore, some striped animals are meat eaters.
Syllogism 4
Some people who never have to work on a Sunday unless their boss calls them Saturday are people who raise chickens in their back yard without a farming permit.
Some people who never have to work on a Sunday unless their boss calls them Saturday are people who have a bad sense of direction but manage to get around using maps.
Therefore, some people who have a bad sense of direction but manage to get around using maps are people who raise chickens in their back yard without a farming permit.
Syllogism 5
Some genin are shinobi.
All shinobi are ninjas.
Therefore, some ninjas are genin.
Syllogism 6
No devil-fruit eaters are good swimmers.
All Whitebeard Pirates are devil-fruit eaters.
Therefore, no Whitebeard Pirates are good swimmers.