Final answer:
Aristotle's first species of justice relates to the human realm of relationships, governance, and individual virtue, focusing on achieving a flourishing life (eudaimonia) through the cultivation of virtues.
Step-by-step explanation:
According to Aristotle, the domain of the first species of justice is rooted in the relationships, justice, friendship, and government of the human world. This concept emphasizes the importance of social interactions and the need to study them for understanding ethics and justice. Aristotle's perspective is very much focused on the observable world and our experiences within it, unlike Plato, who posited forms in an otherworldly realm. Aristotle's Nicomachean Ethics emphasizes that since humans are social beings, these relations are vital for rational and virtuous development. Thus, the first species of justice, as conceived by Aristotle, pertains to human flourishing and the achievement of eudaimonia, or a life well-lived through the cultivation of virtues.