The Brain & Mind

Unlike the brain, the mind is not an organ. It is invisible. It follows you wherever you go even in your sleep. You can neither locate nor touch it.
Your consciousness is your state of being aware of your thoughts and feelings and your surroundings. It, however, may be blocked. Among the reasons are your perceptions, beliefs, and mental programming.
You must have heard and read about the conscious and subconscious mind. To put it simply the former is within your conscious awareness while the latter is "on automatic" where you don't have to think about something but yet it does everything.
A simple example is when you are driving to a familiar location. You don't realize you've reached a certain point until you notice that you have to make a decision at that point of time.
The same thing happens with your thoughts and feelings. Have you ever noticed how your memory of the past, your thoughts and your feelings change from one to another in a day? All it takes is something to trigger them and you will find yourself thinking and feeling and they are usually the same and familiar stuff?
Most of your mental activities that influence your daily behaviors happen without your awareness. They are produced from your habitual mental patterns of thoughts and feelings stored inside.

About Life and Living

What is the meaning of life? What is the purpose of our existence?

Opinions, beliefs and convictions vary from person to person. You can see a person's outlook from the actions that he takes, his health condition, the people he hangs around with, his attitude, his contributions, and his habits.
The majority of people alive are doing their best to feel comfortable. They do wish for better things but they don't make much progress. They are afraid to move out of their comfort zones. They go about their routines. They are up in the morning, rush through the traffic to get to work, spend about eight hours at the workplace repeating the same tasks, rush back home, watch a lot of television, eat and then sleep, with some socializing in between. And they call that living.People "died" all the time in their lives. Parts of them died what they made the wrong kinds of decisions - decisions against life. Sometimes they died bit by bit until finally they were just living corpses walking around. If you were perceptive you could see it in their eyes; the fire had gone out. But you always knew when you made a decision against life. When you denied life you were warned. The cock crowed, always, somewhere inside of you. The door clicked and you were safe inside - safe and dead."
Source:About-Personal-Growth.com