UNANSWERED QUESTIONS MEGA-COLLAB: http://youtu.be/UFydagCS9fg Follow me: http://www.twitter.com/tweetsauce LINKS/SOURCES: music by: http://www.youtube.com/user/jakechudnow/ song at end: "Pious Reflection" by Paul Mottram downloaded from http://www.audionetwork.com/ it's on YouTube: http://www.youtube.com/watch?v=1kszd5IGq_k Human senses: http://science.howstuffworks.com/life/question242.htm http://en.wikipedia.org/wiki/Sense Color illusion: http://loriputnampaints.blogspot.com.es/2010_03_01_archive.html Audio illusion: https://www.youtube.com/watch?v=u9VMfdG873E temperature illusion: http://exs.exploratorium.edu/exhibits/hot-and-cold/ Tactile illusions: http://en.wikipedia.org/wiki/Tactile_illusion epistemology wiki pages: http://en.wikipedia.org/wiki/Epistomology http://en.wikipedia.org/wiki/Knowledge http://en.wikipedia.org/wiki/Theory_of_justification proof: https://en.wikipedia.org/wiki/Proof_(truth)