Trying to define life

I once had a nice discussion with my friends on the definition of life or living thing. Our discussion went for more than an hour and we had to stop it because it is the closing time of mess.I would like to share that experience.
The main difference arose because some of us thought against calling plants as living things.I present a small part of the argument.I would like the readers to develop the argument.Some of you may say it is just the way you define life, after all anyone can define anything in anyway he wants to.But I just want you to think it beyond language barrier.You see,our argument went like this:
Person 1: We can call something as a living thing only if it can have feelings i.e., it should have sense of pain, at least.The bottom line is it should have brain. Now, everybody knows that a plant doesn't have brain.
Person 2: What you say is precisely correct but this need not be the basic need for life.The basic amazing thing about this phenomenon to give it a name, LIFE, is its ability to reproduce.The very thought of one identical thing coming out of another, I mean cell division, is so exciting and great that man called it Life.Infact, if you see, this is precisely why mother is given a special place and mother's love is considered to be the ultimate.
Person 1: See how you are coming back to a FEELING finally,love in this case. Why is cell division so important?Even if cell division is great it has no sense of existence unless there is thought,right?So, only a thing that has brain which is responsible for feelings should be considered as living.
Person 2: Ok, let me put it this way.What is the opposite of LIFE?
Person 1: DEATH.
Person 2: When do you say a man is dead?
Person 1: When his heart stops pumping blood i.e., it stops beating.
Person 2: Precisely! It is not when the brain stops working right?Infact, that is why we have seperate term braindead for that organ. You knew that after heart stops beating,the brain can still function for a few minutes, right? So similarly life is when a nervous system is there and reproduction is there.
Person 1: But still don't you think if you call cell division as life, we should also call any chemical reaction as life?
Person 2: Dude, here we are getting identical being.That is not the case with a chemical reaction.
Person 1: Ok, that was a wrong point but................................

It went on like this.Isn't it interesting?