Life requires a specific chemistry. Our body is powered by chemical reactions and depends on the laws of chemistry operating in a uniform fashion. Even the information that makes up any living being is stored on a long molecule called DNA.
Life as we know it would not be possible if the laws of chemistry were different. God created the laws of chemistry in just the right way so that life would be possible.
There is one God, and only one way to Him, and for this we employ a complete and definite science, oldest of the oldest, most ancient and natural, which is the practical side of all religions of the world as borne out by all the scriptures.
This subtlest of all sciences is called Para Vidya, which has a practical aspect and is the way back to God during lifetime. These days this science is called Sant Mat. It is true nobody can know God. Past masters cannot help, and man needs a living Godman to understand things which one cannot follow by mere theory. Therefore, a living master is necessary to gain the practical side of this science. Unless the experience of past masters becomes our own experience, we get nowhere.
God power works on a chosen human pole. A living master is, therefore, God plus man, Godman, i.e. the mouthpiece of God. Guru, a word often used, is a corresponding word in Sanskrit. A guru is one who can remove the dark veil within and show us the real light of God.
In this age of science, spirituality too has to be treated as a regular science, to make it acceptable to the people. Unlike other sciences, it is very definite and very exact. It yields verifiable results of perennial value. Theory precedes practice. The practice leads to contact with the living link within.
For this experience, the soul must temporarily disconnect itself from the body and senses and become a pure soul with no strings attached. Nanak says: Unless one rises to the level of God, one cannot know God.