int a = 0; a = 1; Same variable, but the value stored changes over time. Consider the human body to be like a variable. The value stored changes over time. Wh

int a = 0; a = 1; Same variable, but the value stored changes over time. Consider the human body to be like a variable. The value stored changes over time. When we use "I" in the present, we are talking about the "value" stored in our body in the present. When we use "I" in the past, we are talking about the value that was stored at a different time. That is how we can refer to systems that change over time using the same identifier - by treating them the same way we treat variables.