1. Words you might need to know
Objectively -- Thinking of something without being influenced or biased by the human mind.
Subjectively -- Thinking of something and being influenced or biased by the human mind.
For example, if we lived 10,000 years ago, we'd look around us and the Earth would look flat. The sky would look like a big dome. Subjectively, the Earth is flat. Objectively, however, the Earth is still round, despite what we think.
2. What is Nihilism?
Nihilism can be broken up into several subcategories, but I'll be focusing on the two that aren't borderline New Age: Moral nihilism and existential nihilism.
Existential nihilism is the belief that nothing has any inherent value, meaning, or purpose.
Moral nihilism is the belief that, objectively, no action is preferable to another. Helping that old lady cross the street and eating kittens are not inherently good or bad.
(I know you might be thinking "lock this guy up; he's a monster!", but give me a few more paragraphs to really explain my position.)
3. Why do I believe it?
From my other article on nihilism:
Imagine that you're playing poker and you happen to get these five cards:
A♠ K♠ Q♠ J♠ 10♠
You, of course, put on your stoic poker-face and deftly win the whole game. You toss those five cards on the table, rip your shirt in half, make a bunch of primitive, caveman-esque grunting sounds and buy yourself a dozen cars, and maybe a house or two.
If you showed those cards to someone who's never played poker before, instead of to the people you were playing against, you'd be forced to repeat "really?! you don't get it?" about a dozen times before you walked away, wishing you could find someone who understood how awesome that hand was.
Objectively, those cards are just pieces of paper, but they subjectively have value. It makes sense that everything just is, and that we, the human observers, are pretending things have value.
There you go. Everything is meaningless!
"Meaningless", of course, is a very negative word, but it shouldn't be. Everything simply is. It has no meaning, either good meaning or bad meaning. It just is, and we subjectively assign value and meaning to things.
Naturally, we don't want to die. We don't want someone killing us. We don't like death in general. Subjectively, killing is a very, very despicable thing to do.
But is it despicable to pull the batteries out of your wristwatch?
Objectively, the only difference between a wristwatch and a human being is the complexity. A wristwatch stops working when you pull the batteries out, a human stops working when you pull any number of vital organs out, but, objectively, killing is neither right or wrong... it just is.
Why don't I just kill people, then? [Pending hyperlink to an article I haven't written yet]
4. Why do people typically oppose Nihilism?
"God is the originator of morals. To say there isn't an objective Right and Wrong is to say God doesn't exist!"
Demonstrate God exists and I'll be happy to agree to an absolute Right and Wrong.
"Why don't you just kill yourself, then, if you think life is meaningless?"
Life just is. It inherently has neither positive nor negative value. Everyone assumes "meaningless" implies reprehensibility, but it doesn't; it's simply a statement of neutral value.
But, to answer the question, I don't kill myself because I, against all objective reason, logic, and rational thought, love being alive and don't want to die.
"You're a music major! Isn't that hypocritical of you to be a nihilist and pursue a career in the arts?"
I guess it is. Objectively, music may be just a bunch of vibrations, but that doesn't mean I can't subjectively find it extremely moving, affecting, and beautiful.
5. What will it take to change my mind?
It's easy to demonstrate subjective value -- I'm a musician, after all, and I get intense emotional pleasure, meaning, and value from playing music -- but it's extremely difficult to demonstrate objective value. In order for things to have objective meaning, I think the only way you could do it would be to demonstrate that there is a God who gave everything inherent value and meaning.
Again, I can't think of anything else that would disprove the nihilist view, but that doesn't mean there isn't something out there.