8.4 Predicate Logic: Condition & Indirect Proof 

Sir... you made me actually understand natural deduction. Something I did not learn in weeks of university. Through that I actually started to have fun solving them... that´s kinda crazy. Thank you very much for posting this on youtube,

I owe you my life! ! Thank you, thank you and thank you! !

LOL .. " .. if you're at a coffee shop, people see you doing this problem and they think that you are a brilliant mathematician .. but it's actually very easy .. "

Thanks for making these videos!

Anyone have a solution for 8.4.1 #17? ...or know of a help forum for Hurley's book?

Like :)

Stop apologizing for your handwriting. I can read it well, and it is legible. :D