Ockham’s Philosophy: Essence, Existence, and Knowledge

The Notion of Essence in Platonic and Aristotelian Philosophy

Plato and Aristotle’s View

Both Plato and Aristotle considered the notion of essence as fundamental for understanding reality. They believed that things in the world derive their identity from a single essence.

They attributed universality and necessity to essence. Universality implies that for every group of particular things sharing the same identity, there is one essence. Necessity means that the essence cannot fail to exist; it must always be.

Ockham’s Rejection of the Notion of Essence

Ockham’s Break with Greek Metaphysics

In the fourteenth century, William of Ockham initiated a departure from Greek metaphysics. This involved rejecting the notion of essence.

Ockham rejected essence due to its incompatibility with two premises of his theology: the Christian doctrine of creation and his own concept of divine freedom.

First Premise: The Christian Doctrine of Creation

Christianity asserts that the universe was created by God (creationism).

The Christian idea of creation differs significantly from the Platonic view for two reasons:

  • The role of nothingness: Christianity posits that God created the universe from nothing. Plato, however, believed that the Demiurge, when shaping nature, worked with pre-existing factors: ideas and matter.
  • The importance of freedom: Christianity emphasizes that God created the universe freely. The Platonic Demiurge, on the other hand, does not act freely but follows the guidelines set by ideas.

According to the Christian doctrine of creation, the universe is contingent. Since God created the universe freely, He could have chosen not to create it or to create it differently. Therefore, the entire universe could have not existed or could exist in a form different from its current state.

Second Premise: Ockham’s Conception of Divine Freedom

Ockham argued that since God is omnipotent, His freedom is unrestricted (unlike human freedom).

This total freedom of God corresponds to a total contingency of the universe.

The Contradiction Between These Assumptions and the Notion of Essence

In a philosophy that embraces total freedom and contingency, the Greek notion of essence has no place. Essence is characterized by necessity, which is contrary to freedom and contingency.

Ockham, remaining faithful to his theology, rejects Greek essentialism. Greek essentialism is incompatible with Christian creationism.

Ockham’s Assertion of the Notion of Existence

Replacing Essence with Existence

Ockham replaces the notion of essence with existence. This emphasis on existence is influenced by the Christian doctrine of creation. According to this doctrine, existence is what the universe receives from God. God, by creating, brings existence from nothingness.

The Nature of Existence

For Ockham, existence has two characteristics that are opposite to those of essence:

  • Particularity: While essence is universal, existence is particular. Each being has its own unique existence, not shared with any other being.
  • Contingency: While essence is necessary, existence is contingent. Beings may or may not have existence, and when they do, they can lose it (and in fact, they do lose it over time).

A third characteristic is added: translucency. For Ockham, existence is transparent to reality.

The Universe Conceived in Existence: The Real Individuality and Contingency of Natural Laws

Based on the characteristics of existence, particularly particularity and contingency, we can deduce how the universe is conceived.

Individuality

Individuality implies that the universe consists exclusively of individuals.

Individuals are obvious, meaning they do not belong to any transcendent or latent realm (like Plato’s or Aristotle’s Forms) but are directly present. The universe does not contain hidden realities beyond the obvious; it is a universe without deeper meaning.

Individuals, besides being obvious, are not opaque. This means that when we perceive them, there is no reality beyond them that makes them perceivable. In this regard, Ockham is the antithesis of Plato, for whom individuals are opaque because they allow us to perceive Ideas.

Instead of opacity, individuals are diaphanous or transparent. This means that something is revealed with absolute reliability. To say that individuals have clearness is to say that they possess something that makes them a target for a certain and error-free vision.

The diaphanous aspect of an individual is its existence, for two reasons:

  • Existence makes it visible: According to Ockham, the existence of a thing causes it to be perceived. For him, vision is linked to existence because if something does not exist, it cannot be an object of vision.
  • There is no difference between what makes it visible and what it truly is: The existence of a thing not only makes us see it but also allows us to see it as it truly is.

Since individuals within the universe are diaphanous, there is nothing hidden in the universe.

Contingency

Contingency implies that the laws of the universe are contingent.

This aligns with Ockham’s conception of divine freedom. According to his view, God’s freedom is above the laws of the universe, which are merely expressions of His will.

Ockham’s Conception of Knowledge

Presence and Absence as Places of Knowledge

Clearness implies that the existence of an individual is linked to its perception.

However, if an individual is absent, then, while still real, it is not perceived.

For Ockham, vision is the highest form of knowledge, and absence is the negative factor that prevents it. For Plato, vision is attached to essence and refers to universal entities (Ideas). For Ockham, vision is linked to existence and refers to particular beings (individuals).

Therefore, for Ockham, there are two distinct cognitive faculties: one for presence (vision) and another for absence (knowledge without vision).

Knowledge in the Presence (of Individuals)

Knowledge and Clearness: Intuition

For Ockham, when something is present, it produces in us an intuition (“intuitive notitia”), which is a direct acquaintance.

The intuitive knowledge of a thing provides us with its translucency.

This knowledge is a secure or clear vision because the intuitive knowledge of things is not a representation but a clear vision of them. This is verified in our lives at every moment.

Intuitive Knowledge: Definition, Properties, Scope, and Limits

Definition

Ockham defines intuitive knowledge as the direct mental apprehension of a present and existing reality.

Properties

Intuitive knowledge is:

  • Intellectual: The intuition of a thing occurs in the intellect, not in the senses.
  • Immediate: The intuition of a thing is produced directly from the sensations we have of it, without any intermediary operations between sensations and intuition.
  • Clear: When we intuit something, we are certain of it, so we do not doubt the truth of what we know.
  • Co-existent with things: This knowledge arises simultaneously with the existence of things. The reason for this is that it is tied to their existence.
  • Created by God: If intuitive knowledge is a source of knowledge about things, and the origin of things is creation, then creation is also the source of intuitive knowledge.
Scope

Intuition allows us to know with certainty the existence of individuals, their qualities, and their relations or connections.

Intuitively knowing these facts is knowing “contingent” facts because they refer to qualities that may or may not occur and may lose their truth.

Therefore, the scope of intuitive knowledge is identified with the field of contingent truths.

Limits

Intuition is limited for two reasons:

  • It can only occur in the presence, not in the absence of an object.
  • It only provides particular knowledge, not general knowledge.

The second limitation implies that intuitive knowledge is not scientific. Science requires general knowledge because it seeks stable laws, which are general. Since intuition does not provide general knowledge, intuitive knowledge is not scientific. If we only had intuition, science would not exist.