This was a tough lecture to listen to, but here is the bottom line:
If one truth implies another truth, the implication is true.
If the truth implies a falsehood, the implication must be false. A single truth cannot imply both a truth and a falsehood.
If a falsehood implies either a truth or a falsehood, the implication must be true. The antecedent must be true to imply anything.
I will post assignment 3 here in a few minutes. Ugly story: My house was broken into this summer and all of my electronics were stolen. I replaced my nice laptop with a new one that has Windows 8, a great operating system for touchscreens but it sucks for laptops. Because Adobe Acrobat is considered a "Windows App", Windows 8 only allows it to be shown full screen. I can't look at the PDF, then copy and paste the text into this blog, or even type as I am looking at it. Because my printer is old (it takes a while to replace electronics!), it won't talk to Windows 8. So, I need to email the PDF to my son (whose computer WILL talk to the printer), get him to print the PDF, and then type.
Ugh!
If I get it correctly, implication leaves out causality. Because of this, a true implication is not a genuine implication,since the latter DOES include causality. I conclude: "true" doesn't equal "genuine" in the math world. Who knew! Nancy Colbert
ReplyDeleteI'm sorry to hear about your break in!
ReplyDeleteI agree that those Win8 apps are super-annoying. Just download the Adobe Reader, and you'll be able to view PDFs in their own windows.
The Reader installer also installed McAfee Security Scan Plus without your asking (lame), but you can easily uninstall it.
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ReplyDeleteDiane, I'm still struggling with quizzes 1 & 2 in Lecture 4. You haven't put up a Lecture 4 topic-title. Did you want to do that, or should we continue here? Seems like the former would be a better idea.
ReplyDeleteI've been struggling with a computer crash and subsequent rebuild this week (a DIY computer rebuild which hasn't gone well, probably to a DOA power supply or mother board). So, I'm a bit late to the party at the moment.