Mentalism - everything has a spirit, a consciousness
Cause and Effect - every cause has an effect, every effect has a cause
Correspondence - as above, so below
Resonance - like attracts like
Balance - everything tends toward a state of equilibrium
Vibration - all is energy, in constant motion
Polarity - everything has a set of poles
These create a neat outline of some of these concepts that I have learned from nature. If you look around you, you can observe the seven Hermetic principles in everything. The law is simply the law of nature, the underlying metaphysics that make logic, mathematics, physics, biology, chemistry, astronomy and geology possible. I've obseved thes principles in my economics courses in college, and I've seen them in Newton's laws. I've watched them play out in relationships with people, and I've watched them play out in magic.
Understanding the way things work means that you can flow with it better, and have better ability to change the current when necessary. It means that my ethics can be grounded in things that are observable truths, not dictates from some memeplex that may or may not have my best interests in mind.
It's not so cut and dry as having a dogma to guide you. I had to screw up from time to time to learn. I had to suffer. But the knowledge I gained is my own, won through navigating my way through the challenges life has to offer. I know it's true because I have experienced it.
I often say that we are a religion in which we are all our own priest and priestess. We may take up the roles of guides and mentors, teachers and helpers, but ultimately, nobody can bestow that kind of enlightenment upon anyone else. We can take you to the door, but you've got to walk through yourself. Ultimately, nobody can bring the divine to you but you.
No man can reveal to you aught but that which already lies half asleep in the dawning of your knowledge.
The teacher who walks in the shadow of the temple, among his followers, gives not of his wisdom but rather of his faith and his lovingness.
If he is indeed wise he does not bid you enter the house of his wisdom, but rather leads you to the threshold of your own mind.
The astronomer may speak to you of his understanding of space, but he cannot give you his understanding.
The musician may sing to you of the rhythm which is in all space, but he cannot give you the ear which arrests the rhythm nor the voice that echoes it.
And he who is versed in the science of numbers can tell of the regions of weight and measure, but he cannot conduct you thither.
For the vision of one man lends not its wings to another man.
And even as each one of you stands alone in God's knowledge, so must each one of you be alone in his knowledge of God and in his understanding of the earth.