1 / 22

Can you think of five famous people who you feel are rational/logical?

Can you think of five famous people who you feel are rational/logical?. Deciding whether a syllogism is valid. Trying to decide if a syllogism is valid is not easy. Venn diagrams can help (at last a good use for Venn diagrams!). Deciding whether a syllogism is valid. Mmmmmmm…Vodka!.

durin
Download Presentation

Can you think of five famous people who you feel are rational/logical?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Can you think of five famous people who you feel are rational/logical?

  2. Deciding whether a syllogism is valid Trying to decide if a syllogism is valid is not easy. Venn diagrams can help (at last a good use for Venn diagrams!)

  3. Deciding whether a syllogism is valid Mmmmmmm…Vodka! • Some IB students are from Russia • All Russians are good at drinking vodka • Therefore some IB students are good at drinking vodka Is this a valid argument?

  4. Using Venn diagrams • Some IB students are from Russia IB Students who are Russian IB Students Russians

  5. Using Venn diagrams • All Russians are good at drinking vodka Good vodka drinkers IB Students Russians

  6. Using Venn diagrams • Therefore some IB students are good at drinking vodka Good vodka drinkers IB Students Russians

  7. Another example • All As are Bs • All Bs are Cs • Therefore all Cs are As

  8. Another example • All As are Bs A B

  9. Another example • All Bs are Cs A B C

  10. Another example • Therefore all Cs are As These Cs are not As A B C The syllogism is not valid

  11. Another example! • All As are Bs • Some As are Cs • Therefore some Bs are Cs

  12. Another example! • All As are Bs A B

  13. Another example! • Some As are Cs A C B

  14. Another example! • Therefore some Bs are Cs A C B The syllogism is valid

  15. Now your turn Using Venn diagrams in your notebooks, decide whether each of the following arguments is valid or invalid.

  16. Valid or invalid • All Norwegians eat hotdogs • Edward eats hotdogs • Therefore Edward is Norwegian

  17. Valid or invalid • No Swedes have red noses • Mr Luitjens has a red nose • Therefore Mr Luitjens is not a Swede

  18. Valid or invalid • All IB1 boys are brave • Some brave people are compassionate • Some IB1 boys are compassionate

  19. Valid or invalid • Some physicists are frauds • Some frauds are not wealthy • Therefore some physicists are not wealthy

  20. Valid or invalid • All Norwegians have dogs • No good football players have dogs • Therefore no Norwegians are good football players

  21. Valid or invalid • All clever girls are red-headed • All red heads are rich • Therefore all clever girls are rich

  22. Valid or invalid • No teachers are clever • No IB1 students are clever • Therefore no IB1 students are teachers

More Related