Once we understand there is Truth, then we must also recognize that there are lies, and there is a battle between Truth and Lies.
Truth vs Lies
Two children standing in front a pool of water,
Hany: Farid this is a deep pool of water, if we go there we will drown since we can't swim.
Farid: I don't believe there water, and I really don't understand what water is.
No if both children go into the pool what do you think will happen:
A) Hany will drown because he believes there is water, but Farid will be saved because he does not believe in it?
B) Both will drown because they can't swim and the water is deep
The Truth is:
If water is deep and you can't swim, you will drown. regardless of what you think.
The Truth War
According to Scripture, the ages-old conflict over the truth is spiritual warfare-- a cosmic battle between God and the power of darkness (Ephesians 6:12) 
- The Truth War, John MacArthur