Is metaphysics a science?

Is metaphysics a science? This question is answered by Kant in the preface to the second edition of the Critique of Pure Reason. The goal of the preface is to explore whether metaphysics, at the time Kant is writing, is a science, whether it can be a science and what would be needed for metaphysics to be a science. In order to understand what Kant has to say about metaphysics, let’s first understand what metaphysics is!

Metaphysics is a branch of philosophy that asks big questions about things that go further than our experience alone. These questions cannot be answered by science. For example, in the time of Kant, metaphysicians were mainly working on 4 questions: Does God exist? What is a soul? Do we have freedom? What is being? This branch of philosophy dates back to Aristotle and his work Metaphysics, even though Aristotle did not name this work himself. In this work Aristotle seeks a science which he calls first philosophy. This science is occupied with first principles (starting points) and should examine the first causes on which the rest of reality depends. This science should go beyond physics (hence the name) and explore topics which physics and other sciences cannot explore. Seeing the history of philosophy, it is hard to say whether metaphysicians have actually found this science or whether we are still looking for it. Nevertheless, metaphysics was a very popular branch of philosophy for mediaeval and modern thinkers. 

Most philosophers who have occupied themselves with metaphysics first present a method to be followed that assures them that they take no wrong turns and then apply this method to explore metaphysical topics. Take, for example, Descartes’ meditations. The name Meditations on First Philosophy announces that this book is about metaphysics. This is also clearly seen when we consider the topics on which it touches: the existence of God and the soul. Descartes first provides us with a method which should allow us to practise metaphysics without being mistaken: radical doubt. Then Descartes applied this method to metaphysics and pretended to find knowledge on the soul and the existence of God. 

If we get back to the question at hand, we also must understand what science is.

What is science?

Kant first provides us with two negative criteria for science:

1. Disagreement on the results

A science, in order to be a science, should be able to demonstrate their results. If a science can demonstrate its results, then a disagreement should not be possible for those who practise such a science to disagree on the results. What is decisive here is that agreement is seen as a consequence of truth. This means that, where there is no agreement among those who practise a discipline, there cannot be a science. If we think about mathematics, for example, a mathematical proof does not leave any room for disagreement, and mathematicians are not known for their disputes about the results of simple mathematics. 

2. Disagreement on the method

Since a science should be able to demonstrate their results, there should also not be any doubt about the methods used by a science. The methods of a science should always lead to a true result. For example, if we apply the research methodology of physicists, then there should be no doubts about the results that come out of such research. They either prove something is right, prove something is wrong or demand further research. Nevertheless, the results of research done properly are never wrong. 

Any discipline that has a disagreement on its method and its results is “groping about in the dark”. This means that such a discipline is not yet a science because its results and its methods are doubtful. What characterises a science for Kant is the certainty with which it produces knowledge. A discipline “groping about in the dark” can obtain truths, but it cannot know for certain that these are truths nor be in possession of a methodology to verify this truth and obtain new ones. 

Examples of science

Kant goes on to examine three sciences to expose their scientificity:

1. Logic

The logic that Kant has in mind here is the logic of Aristotle developed in his Organon. This science examines the conditions for valid and invalid reasoning by considering the mere form of an argument. Logic looks at rules for thinking. They ask whether a conclusion follows from the propositions given. However, they do not examine the propositions they are working with; they merely examine whether the conclusion logically follows from those propositions. 

What assures that logic is a science, according to Kant, is that “since Aristotle, it has not been forced to make a step backwards”. This is a sign that its methods and its results are certain and therefore prove it is a science. Another sign is that logic has also been unable to make any step forward, which means that its methods are solid, as they have never had to give way to any other methodology. 

What made it so easy for logic to develop into a science is that logic does not have to occupy itself with any objects; rather, it merely considers the form of reasoning. This privilege is not shared by any other science. Other sciences must occupy them with objects. According to Kant, other sciences must have some a priori knowledge of their objects. This is a positive criterion for science. What is a priori knowledge? A priori knowledge is necessary and universal knowledge that does not come from experience. For example, “All bodies are heavy” is an a priori judgement, as knowledge of all bodies cannot come from the senses alone. 

2. Mathematics

Mathematics is one of the sciences that Kant considers to have a priori knowledge of its objects. Mathematics, according to Kant, became a science once it makes synthetic a priori judgements and verifies them in experience. Synthetic a priori judgements are a priori judgements that tell something new about a concept. Since heaviness is not included in the concept of a body, the judgement “all bodies are heavy” is synthetic a priori knowledge. According to Kant, it was Thales who revolutionised mathematics and made it a science. It was Thales who first tried to make synthetic a priori judgements and verify them in experience. What Thales did was he first thought of a mathematical rule: “If line AC is the diameter of a circle and B is another point of that circle, then B must be a right angle.” After thinking of such a rule, Thales verified in experience whether this was true or not. This revolution of the method made by Thales introduced synthetic a priori judgements into mathematics and therefore made it a science.

3. Physics

Physics took much longer to become a true science according to Kant. Kant attributes the scientificity of physics to Galileo, Torricelli and Stahl. What these physicists did right according to Kant is that they first worked out a theory and then put that theory to the test. This is quite the radical change from the physics that took place before this. Physics, before this revolution, contented itself with knowledge derived from experience alone. For example, by tracking the movements of the planets in the sky for long enough, some physicists could predict their movements with great accuracy, but not with certainty. It wasn’t until the laws of Newton, which are synthetic a priori laws, that we could say with certainty how planets ought to move. 

Is metaphysics a science?

Kant’s answer: not yet! But it can become a science. Metaphysics quite evidently corresponds to the two negative criteria given by Kant. There is disagreement on method and on results. Kant calls metaphysics an “arena of endless contests”. This is because every author poses his new foundation, method and results. No one has been able to keep the ground that they have won for long. Before long there is another author, with new foundations, a new method and other results. Metaphysics has, up until Kant, “groped about in the dark” without ever assuring anything. 

What metaphysics needs is synthetic a priori knowledge that can be verified in experience. Is it possible for metaphysics to become a science? That is the guiding question answered in Kant’s first critique.