Kant's Metaphysics

Background: The Conflict between two accounts of how knowledge of the world of experience (the domain of natural philosophy or science) is to be understood: These two accounts are Rationalism and Empiricism

Rationalism: the source of knowledge is reason; emphasizes the importance of mathematics in scientific knowledge. [Representatives include Descartes (1596-1650), Spinoza (1632-77), and Leibniz (1646-1716)]

Empiricism: the source of knowledge is experience; emphasizes the importance of experiment in scientific knowledge.[ Representatives include Locke (1632-1704),Newton (1642-1727), and Hume (1711-76)]

Between Descartes and Kant (1724-1804) much progress in scientific knowledge had been made. The new science is exemplified by Newton's unification of mechanics and astronomy, but includes many sucessors including Boyle (gases), Lavoisier (chemistry), and Franklin (electricity)

Hume: The contents of the mind are of two kinds: (1) Ideas derived from (sense) Impressions (experience) (2) Relations of ideas examplified by mathematics. Only statements concerning relations of ideas can be necessarily true. Hume argued that the idea of Necessary Connection is part of the idea of cause and effect,but experience can never be the source of that idea. Experience only show the constant conjunction of cause and effect Therefore, we cannot have knowledge of cause and effect.

Kant's tasks: (1) To unify Rationalism and Empiricism that is, to show how (scientific) knowledge is possible, and how both reason and experience contribute to that knowledge. (2) To refute the skepticism of Hume who claimed that experience (and reason for the matter) is extremely limited in what kind of knowledge it can provide.

Kant wanted to show that truths which are necessary like mathematics but apply to experience like sense impression are possible. Scientific knowledge of the world of our experience which is Universal and Necessary is possible. Kant's metaphysics is his a ttempt to show how (scientific) knowledge is possible.

Some Technical terms used in Kant: A Priori Truths: Truth which is independent of experience, a necessary truth A Posteriori Truths: Truth which is based on experience, contingent Analytic Judgment: A judgment in which the concept of the predicate term is found in the concept of the subject term. (often called true by definition) Synthetic Judgment: A judgment in which the concept of the predicate term in not found in the concept of the subject term. Kant's task is to show how synthetic a priori truths are possible.

According to Kant, knowledge is to be understood in terms both of Intuition, that which is immediately before us through perception and Reason which is the way the mind organizes perception so that it becomes the object of experience.

The Forms of Intuition: Space (the outer form, spatial relations of geometry) Time (the inner form, linear sucession of arithmetic)

The Forms of Judgment: Aristotle's logic: necessary preconditions for any possible thought. From the 12 forms of judgment Kant deduces the Categories of experience. The categories are the means by which the human mind organizes percepts of to form objects of experience. In terms of knowledge the most important of the castegories are those of Relation: (1) Of Inherence and Subsistence (substance and property) (2) Of causality and Dependence (cause and effect) (3) Of Community (reciprocity between agent and object)

The Categories are the necessary preconditions for the kind of knowledge exemplified by Newton's science. They are both synthetic and a priori, and are the contributions of Speculative Reason to knowledge.

Kant's synthesis of Rationalism and Empiricism: "Concepts without percepts are empty; percepts without concepts are blind."

Speculative reason is the faculty of knowledge; Practical reason is the faculty of choice (the Will)

The Laws of Logic are necessary for any kind of thought

Kant draws parallels between the domains of Speculative Reason (natural philosophy) and Practical Reason (moral philosophy)

Speculative reason The Categories Metaphysics of Nature Metaphysics of Morality Generalizations from experience Appearances

Practical reason

The Supreme Principle of Morality Natural Philosophy (science) Moral Philosophy (anthropology) Maxims Actions

Kant's problem in respect to speculative reason was to show how knowledge was possible. Kant's problem in respect to practical reason was to show how moral judgments are possible. Kant's understanding of scientific knowledge greatly influences his view of morality. For Kant knowledge, both scientific and moral, must be universal and necessary.