Our zero universe of equilibrium demands two opposed conditions in order to simulate that which our senses interpret for motion and change. These to needed conditions are plus and minus equilibrium; positive and negative electricity.
Plus zero means a credit of pressure borrowed from the universal equilibrium to compress a large volume into a small volume. Minus zero means an equal expansion to balance the borrowed compression.
A thousand dollars borrowed from a bank is a plus condition of credit which is balanced by an equal debit of one thousand dollars. The central zero represents the bank. The extended zeros represent credit and debit. Both are equal but opposite. A credit of one thousand dollars equals zero [for the bank]. When the credit is paid in part or in full the debit is proportionately voided simultaneously with the credit. [Terms of interest disturb this system inevitably.]
These two opposite conditions of credit and debit correspond with the two opposite conditions of compression and expansion in Nature upon which motion is dependent. When an equilibrium pressure is divided into opposite conditions from the zero from which both are extended, motion between the two becomes imperative. They must interchange with each other to void their unbalanced conditions. This is the principle of the electric current.
(Walter Russell, The Secret of Light, pp 230-231)