Final answer:
Isaiah is demonstrating the principle of kairos by understanding the importance of timing in his decision to start a family after completing university.
Step-by-step explanation:
Isaiah is demonstrating the principle of kairos, which refers to the right, critical, or opportune moment for action. In this context, Isaiah understands the importance of timing and is able to balance his strong desire to have a family with the practical consideration of completing his university education first. By doing this, he is showing an awareness of the timeliness of life decisions, much like the concerns these college graduates have about their lives after graduation, as mentioned by Johnson.