Metaphysics, as the study of the fundamental nature of reality, has long grappled with the question of what constitutes the essence of existence. Two contrasting frameworks have emerged across philosophical traditions: the metaphysics of fullness, which posits a unified, eternal, and unchanging reality, and the metaphysics of emptiness, which emphasizes flux, interdependence, and the absence of inherent essence. The Upanishads and Parmenides exemplify the metaphysics of fullness, asserting a singular, all-encompassing reality, while Buddhism and Heraclitus champion the metaphysics of emptiness, focusing on impermanence and the lack of a fixed substance.
This contrast can be seen as a function in its own right, adding a new function to the established four: thinking, feeling, sensation, and intuition. In Psychological Types, Jung also grappled with this question, as seen from his many quotations from the Tao Te Ching, Buddhism, Heraclitus, and the Vedas. He was a pioneer of the study of metaphysics but ultimately failed to turn his intuition into a coherent, systematic idea.
That the metaphysical function – also referred to as the transcendent function by Jung – has not emerged as a salient component of typology before now can be explained by the circumstance that most moderns have never experienced metaphysical states of mind. In Ancient Greece, also, metaphysical insight was usually taught only in select settings, since the public at large would laugh or fail to understand.
To understand the metaphysical function – M – and its bifurcation into extroverted and introverted orientations – Me and Mi – we must therefore first understand the nature of metaphysics and only then turn to its polarities.
Conceptualizing the Metaphysics Function
We can conceptualize the metaphysical orientation as a cognitive function with two orientations. Here, we propose Extroverted Metaphysics (Me) and Introverted Metaphysics (Mi).
Me, as exemplified by the perspectives of Buddhism and Heraclitus, engage with reality as a dynamic, external process of becoming, emphasizing the observable flux and interdependence of phenomena. This function is outward-focused, perceiving the world as a ceaseless flow where no fixed essence exists. Everything is relational, transient, and subject to change. Heraclitus’ doctrine of panta rhei (“all things flow”) and Buddhism’s Shunyata (emptiness) reflect Me’s orientation toward the external, ever-shifting nature of existence, prioritizing adaptability and an acceptance of impermanence. Me users, in this sense, are attuned to the relational and process-oriented aspects of reality, often seeking to navigate or transcend the world’s inherent instability through practical engagement or detachment, as seen in Buddhist practices aimed at liberation from suffering.
Conversely, Introverted Metaphysics (Mi), as embodied by Parmenides and the Vedantic tradition of the Upanishads, turns inward to apprehend a singular, eternal, and unchanging essence that underlies all appearances. Mi focuses on an internal, unified vision of reality, rejecting the external world’s multiplicity and change as illusory in favor of a timeless, indivisible truth. Parmenides’ assertion of a homogeneous, unchanging “what is” and the Upanishads’ concept of Brahman as the ultimate, non-dual reality exemplify Mi’s drive to distill existence into a coherent, internal principle of fullness. This function prioritizes inward-turning insight over sensory data, seeking a stable foundation of being that transcends the flux of the external world. Mi users, therefore, are inclined to pursue a deeper, often abstract understanding of reality, aiming for unity and permanence. Together, the Me-Mi axis highlights a fundamental cognitive bifurcation in metaphysical thought: one outward and process-oriented, the other inward and essence-focused, each offering a distinct lens through which to interpret the nature of existence.
Contrasts and Implications
The metaphysics of fullness (Mi) and emptiness (Me) present opposed orientations of attunement to metaphysical reality. The Upanishads and Parmenides assert a unified, eternal being. Brahman or Parmenides’ being transcends change and multiplicity. For them, the apparent world of diversity is an illusion (maya in the Upanishads, doxa in Parmenides), and true knowledge lies in realizing the unchanging oneness of reality. This perspective offers a sense of stability and ultimate meaning: in the Upanishads, the realization of Brahman brings liberation (moksha), while Parmenides’ being provides a foundation for understanding existence grounded in what he holds to be “true reality,” the only thing in which one can truly trust.
Conversely, Buddhism and Heraclitus see reality as a process of becoming, marked by impermanence and interdependence. Shunyata and Heraclitean flux deny the existence of a fixed essence, focusing instead on the relational and transient nature of phenomena. This view challenges the notion of permanence, encouraging adaptability and detachment. In Buddhism, understanding emptiness leads to freedom from suffering, while Heraclitus’ flux invites an acceptance of change as the natural order. However, this metaphysics can also evoke a sense of groundlessness: if nothing has inherent existence, what is the basis for meaning or stability? What is there to hold on to or be unhappy about?
Complementary Insights
As with the other four functions, Me and Mi are opposed in orientation but complementary on a deeper level. As Ti dominants often get along with Te dominants, Se types with Si types, and so on, people with well-developed Me and Mi are often fascinated by each other and naturally ‘get’ one another.
Despite their contrasts, the metaphysics of fullness and emptiness offer complementary insights. The Upanishads and Parmenides provide a vision of ultimate unity, addressing the human longing for permanence and meaning. Buddhism and Heraclitus, by contrast, embrace impermanence, fostering resilience and a deeper understanding of interdependence. Together, they highlight the tension between being and becoming, between substance and process, inviting a more nuanced engagement with reality that balances stability with change.
In conclusion, the metaphysics of fullness and emptiness represent two poles of human thought about the nature of existence. The Upanishads and Parmenides, with their focus on a unified, eternal reality, contrast sharply with the impermanent, relational world of Buddhism and Heraclitus. Yet, both perspectives enrich our understanding, offering distinct paths to grapple with the mysteries of being and becoming in a complex, ever-shifting universe.
The Nature of the Metaphysics Function
In Jungian typology, the traditional cognitive functions – sensation, intuition, thinking, and feeling – each serve distinct roles in how individuals perceive and judge the world. Sensation attends to tangible, concrete realities through experience; intuition focuses on the ideational, perceiving patterns and possibilities beyond the immediate; thinking engages in rational judgments based on logic and principles; and feeling makes sentiment-based judgments, prioritizing values and emotional resonance.
Introducing a fifth cognitive function, the metaphysical function (M), adds a new dimension to this framework. The metaphysical function orients the individual toward the fundamental nature of existence itself, seeking to apprehend the underlying essence or process of reality beyond empirical or emotional considerations. It is neither purely perceptual nor judgmental but rather a hybrid mode of cognition that probes the "why" and "what" of being, asking questions about the ultimate structure, unity, or transience of the world. Whether through the lens of fullness (Mi) or emptiness (Me), the metaphysical function drives an individual to explore reality’s deepest truths, often transcending the practical, emotional, or ideational concerns of the other functions.
In practice, the metaphysical function manifests as a deep curiosity about the nature of existence, often leading to philosophical or spiritual inquiry. Though stunted in most people, the perennial traditions hold that we all possess this faculty.
Unlike the other four functions, the metaphysical function can be developed to any level in any individual without polarizing its opposite. It has no counterfunction the way F is the opposite of T or S is the antithesis to N. It is not a question of seeing some parts of reality over others, but of seeing more of reality altogether.
For example, someone aligned with Extroverted Metaphysics (Me) might resonate with Heraclitus’ focus on flux, observing the world’s constant change and interdependence, and thus develop a metaphysics centered on adaptability and impermanence, as seen in Buddhist practices of mindfulness and detachment. Conversely, someone with Introverted Metaphysics (Mi) might align with Parmenides or the Upanishads, seeking an internal, unified truth like Brahman, and thus prioritize contemplation of the eternal, unchanging reality. Unlike sensation, which grounds itself in the here-and-now, or intuition, which leaps toward future possibilities and is, from the metaphysical point of view, both “empirical,” the metaphysical function is concerned with the timeless or noumenal nature of existence itself, often leading to abstract, existential, or cosmological insights that shape an individual’s entire stance and approach to life. In this way, the metaphysical function complements the other four functions, offering a unique perspective that bridges the tangible, ideational, rational, and emotional with the ultimate questions of being.