Modern computer implementations (physical, CMOS, as well as most virtual machines) almost completely use only binary logic (although some flash memories may use more than 2 states per physical bit cell).
By convention, if you have 1 bit of binary information, or a single logic signal, we call one state “0” and the other state “1”. If that 1 bit addresses 2 bits of memory, then the two addresses are 0 and 1 to match the binary state nomenclature of the address bit.
Early TTL Logic data books labeled the signal state nearest 0 Volts as logic “0” in the truth tables.
Compositions of a small number of logic bits (more than one) are usually numerically interpreted as sums of powers of two times those binary bits, and the minimum unsigned sum is zero.
Many early programming languages grew out of shortcuts for data and program entry via binary switches. The conventions followed.