Irrational numbers, such as pi, cannot be expressed as fractions of integers, which defines rational numbers. The discussion highlights a misunderstanding regarding the nature of pi as a ratio of circumference to diameter, emphasizing that this ratio does not yield a fraction of integers. It is clarified that the existence of a rational circle with both rational circumference and diameter is not possible. The conversation also touches on the broader implications of definitions in mathematics. Ultimately, all irrational numbers remain non-rational by their very nature.