A sixth sense is nothing more than the ability of the subconscious mind to analyze data in a fraction of a second which would otherwise take the conscious mind much longer than the situation allows for. It’s the same as when you for no reason at all suspect someone of having done something without being able to put a finger on it, but your subconscious having all the time in the world knows better.
Throughout humanity a sixth sense is perceived as someone having some kind of mystical ability or some sort of guardian angel, making him aware of something that our normal senses are not even aware of. In reality a sixth sense is the direct result of our conscious and subconscious minds working on different time scales. As you walk out of a shop onto the pavement, and are just about to cross the road, something in your head suddenly tells you “STOP!!!” Moments later a truck rushes by, missing you by mere inches. After recovering from the shock you suddenly realize that your sixth sense has just saved you. But because you couldn’t explain it, you accept it as being some mystical force or phenomenon of some kind. In reality, what just happened here was that your subconscious mind, which operates on a much faster time scale, heard the sound of the truck approaching? It also saw the road and knew you were about to cross it. With your subconscious mind being much faster and with almost all the time in the world to analyze this data, it realized that you were on a collision course with a truck. It also knew that to pass this information on to your conscious mind’s level of awareness, would take far too long in relation to the time constraints imposed between the conscious and subconscious. The quickest way to stop your body was to simply tell your conscious mind to stop by giving it a bold command, STOP!!! After this catastrophe had been averted, you now consciously try to figure out where this sudden warning came from. As there is no conscious communication between these two minds at the conscious level you have no way of knowing that it came from the subconscious level being in control. By this time the whole ordeal is like long gone history to your subconscious mind as if it has occurred literally hours ago and since have been working on hundreds of other events.
On entering a room you might sense that something is wrong, that danger is lurking around the corner. Again this is as a result of your subconscious mind, literally having all the time in the world in unison with all of your senses to analyze the room. By noticing, smelling or hearing something out of the ordinary at supersonic speed it heeds a relevant warning. This all happens in just the first fraction of a second of your entering the room, but from the perspective of your subconscious mind its like having been there for a very long time. Knowing the time constraints of your conscious mind, the subconscious mind has once more issued another urgent warning, like “GET OUT!!!” in order to protect you from imminent danger.