When the resistance of a conductor is constant, is the current proportional to the voltage or is the voltage proportional to the current?

When the resistance of a conductor is constant, is the current proportional to the voltage or is the voltage proportional to the current?

From a mathematical point of view, it doesn't matter which is better than which. From a physical point of view, the current should be proportional to the voltage. Because the current is generated by the voltage, there is voltage before there is current