"If God really meant for us to be able to discern the truth just by picking up the Bible, how do you defend the fact that prior to the idea of Sola Scriptura being created by Martin Luther"
Umm..he wasn't the first
"We had NO denominations before the 1500's"
whoa whoa whoa...yes there were, catholics just killed, excommunicated, or banished them. First noteable one was the alexadria school who had their own pope

Rememeber, back in the day when there were about 5 of them?
"why would you want to lean on your own understanding - alone? "
Common mistakes made by catholics. I don't. I used the writings to guide me as well as peers, but they are not EQUAL to the bible in terms of authority.
"The doctor doesn't allow me to prescribe my own medicine, the police don't allow me to set and interpret my own laws..."
Yes, but we do elect the judges to do so

AND a doctor does ask the symtomes, and anyone can become a doctor, not just people that a group of people choose
"then how come there are 30,000 Protestant denominations"
The same reason there are several views on different issues in the catholic church.
"No, no Protestants contributed one ounce of effort to the bible - but they sure snapped it up and decided to tell the authors that they have no idea what the bible is about."
Umm...no catholics did either for that matter

but we sure as heck helped out with translations.
"You would not have a bible to interpret if it were not for the Catholic Church"
NOw that is funny. The cannon was set LOONNNGGG before your council said it was right. There were only 2 books in real question that are in it. So try that line on someone who hasn't studied history.
"SHOW me in the Bible where Jesus BREATHED on his followers (NOT just the disciples!) and said, "Receive the Holy Spirit. What you forgive will be forgiven, what you hold bound will be held bound in heaven." (John 20: 19-23)"
Just one question, how many people did he appear to and say go preach and make disciples of? hmm? can a non disciple make a disciple? Funny how in Luke 24:36- it used the word disciples and NOT apposlies huh? Jesus has tons of disciples, for they are the people that believed and followed him..ie christians.
"Further, while Jesus told his parables to everyone, he only EXPLAINED them to his disciples. (Matthew 13: 36; Luke 8: 9-10)"
Actaully he only explained one to them

so I guess useing that line of logic we can say you know that one really well but are in the dark on the others huh?
"The entire seventeenth chapter of John is a prayer by Jesus to the Father for his disciples and their journey into the world after he is gone."
Yup, so?Funny how in the last part of that prayer Christ says "and will continue t make you known ..." Funny how also that EVERYONE that was baptised recieves the SAME gift that Jesus gave the apsotlies at penicost (acts 2:3

.
"And Jesus WAS used to preaching to the multitudes."
Yes, the 12 were closest to him, but they made disiciples, many many of them..basically EVERYONE they converted, so there ya have it