Metaphysics: The First Science of Reality and its Principles
1. Philosophical Reflection on Reality
1.1 The Need for a Foundational Science
The positive sciences, as outlined in unit 1, start from postulates, formulate hypotheses, verify them through experience, and transform them into laws and theories. Science, therefore, begins with premises that are as universal, necessary, and obvious as possible to achieve the most certain and true knowledge. The more universal a premise, the more reliable it is, and the more necessary it is, the less likely it is to be erroneous. When a premise is clear, the truth is evident without requiring further proof or dependence on prior premises. Aristotle called this foundational science “first philosophy.”
1.2 Doctrines on the First Science
The existence or need for a first science or foundational knowledge to support all other sciences has not always been accepted. Skepticism doubts the existence of a true reality and argues that even if it exists, we can never be sure of it. Voluntarism holds that the ultimate foundation of knowledge is the will; science helps us understand reality to dominate it. Pragmatism maintains that a theory is valid only if it is useful. Empiricism supports the validity of scientific knowledge but claims its foundation is not universal knowledge but rather individual experience. Transcendental idealism, according to Kant, posits that ideas like soul, world, and God cannot be derived from empirical observation, yet they are necessary to find meaning in life.
From the late nineteenth century to the present, three streams of thought have prevailed regarding human knowledge:
- Irrationalism: denies the existence of objective truth and valid science.
- Enlightenment: values the truth of science for its utility, following Kant.
- Metaphysical realism: supports the existence of objective truths.
2. Metaphysics: The First Science
2.1 Metaphysics as the Science of Being
Sciences are organized hierarchically, with more universal, necessary, and obvious knowledge serving as premises for other sciences. The entire body of scientific knowledge depends on a science with these characteristics. Metaphysical realism identifies this foundational science with metaphysics, which studies reality itself, not just parts or aspects of it. Metaphysics is the science of being qua being.
2.2 Metaphysics as the Science of First Principles
The starting point of metaphysics is reality. We truly know and do science because we can know reality. Concepts have the reality of thought and the reality of the thing itself. These foundational concepts are called first principles, the proper object of study in metaphysics. The most basic first principle is the principle of non-contradiction, which is evident, necessary, and universal. Other first principles include:
- Principle of identity: every entity is identical to itself.
- Principle of excluded middle: something either is or is not; there is no third option.
- Principle of causality: everything that exists has a cause.
3. The Radical Structure of Reality
3.1 Subject and Categories
All reality must have a way of being, which in philosophy is called the subject. In the physical world, things are distinct units, each with properties that can be gained or lost. Substances are the subjects, and their inherent characteristics are called accidents. Substances and accidents are universal categories under which everything can be classified. Aristotle identified nine categories of accidents: quality, quantity, relation, place, time, position, state, action, and passion.
3.2 The Substance of Nature
The intrinsic principle of each substance that determines its specific mode of operation is called its nature.
3.3 The Reality of Change
Changing realities have a determined way of being but also the capacity to become something else. Potency is the capacity to receive perfection, while act is the state of having achieved that perfection. Change is the transition from potency to act. There are two fundamental types of change:
- Substantial change: a substance becomes something different.
- Accidental change: the substance remains the same, but its properties change.