Rene Descartes, the father of cartesian philosophy, puts forward the relationship between sciences and especially the relation of metaphysics with other sciences through a metaphor known as the "Tree of Knowledge." He describes knowledge as a tree and sciences are connected with each other as if they are parts of a tree. Its trunk is physics, its branches are other sciences and the fruit, which is considered to be the goal of a tree, is the science of morals. We are familiar with this metaphor and its varieties in philosophy and Sufism. In particular, it is a common metaphor to accept morals as "the fruit." Morals, which are the intent of scientific activity, are deemed worthy of being the fruit, or the goal, by many thinkers. As a matter of fact, Ibn Arabi and Qunawi also used the same metaphor. They categorized the science of morals that is often identified with Sufism as the fruit of a tree and the goal of all human endeavors. Descartes completes his metaphor by saying that the tree’s roots are metaphysics. It is the roots that sustain a tree; the trunk, branches and fruits all depend on roots and are nourished by them, which makes the roots the most indispensable part. In this respect, this metaphor can be interpreted as a tribute to metaphysics.

While the tree of knowledge designates the place metaphysics holds among sciences, it seems to correspond with classical metaphysics, at least formally. Because the principal and subsidiary divisions of science (root and branch) are used by classical metaphysics to explain the relation of metaphysics with other sciences, the concepts of "principle and subsidiary" can be replaced by "universal and divisive," and the meaning will not change: Metaphysics is a universal science and all other sciences serve to it as its particulars. It separates from other sciences, which examine the being from a specific angle, as metaphysics examines being qua being. Its superiority comes from this unique field of research. Because of its superior status, metaphysics is entrusted with another duty: Universal science is the most fundamental field as it certifies the principles of other sciences. The most controversial part of this assertion is whether such a superior science is possible and, if so, what method it has to attain knowledge. We will get to that, but now it is enough to state that: Despite the formal similarities, it is unlikely that Descartes could form a metaphysical understanding through this metaphor in the classical sense.

As a matter of fact, he couldn’t. The trunk – not the roots – ranked first. In other words, physics stood out among the other sciences, including metaphysics and became the most fundamental science. In this aspect, physics became the raison d’être not only for "branches and fruits" but also for "the roots" and put forward a new perspective of the universe by connecting all the sciences. Physics and its principles became centralized, and the other sciences were re-formed by its principles. In his book "Contemporary Sociological Theories," Russian American sociologist Pitirim Sorokin skillfully pointed out how cartesian philosophy built the humanities and the rules of physics were applied to the humanities. In our time, although this understanding of science has shown some developments in itself, it has never been for the benefit of metaphysics, and metaphysics has lost its classical sense and mission and ended up being a field left to art and poetry.

Lost, more than ever

Metaphysics has never lost its importance and meaning as much as today in its history. We can see this as a failure: Particular sciences that use the method of physics have reduced metaphysics to absurdity and metaphysics could not find a convincing answer to the question of "why is metaphysics important?" On the metaphor of the tree, German philosopher Martin Heidegger raised this question: "What is the soil where the tree spreads its roots?" and claiming that since Aristoteles' metaphysics had had misorientation, he changed the course of the discussion and yet did not contribute to classical philosophy at all. Classical philosophy lost its power first when it was articulated to physics in the cartesian philosophy and then when German philosopher Immanuel Kant claimed that the existence of God and some other metaphysical questions were antinomies. After that, metaphysics became "a nice memory" in the history of philosophy, or rather it was thrown into the dusty pages of history.

We are faced with a serious problem here. We have already stated that the relation between natural sciences and metaphysics, as argued in the metaphor of Descartes, can be found in the classical classifications of sciences, at least formally. Even the name metaphysics (after physics) implies this relationship. This being the case, why did this metaphor lead to a breakaway? The answer to this question would help us understand the current situation. I think it is necessary to focus on two points to understand this: First, the name "meta-physics" is misleading. It implied a methodical relation between natural sciences and metaphysics and yet a definite line was never drawn. We can ask whether this is a continuity relation, but the answer is no because a continuity relation between natural sciences and metaphysics would make metaphysics meaningless and unmethodical. If this was the case, which gap would metaphysics fill? Most of all, a science dependent on physics for its method would get us knowledge mostly according to that science. This would make metaphysics desperate in the face of the criticism of "tautology." One of the false notions about metaphysics is this: Making metaphysics according to physics. This would give the impression that when physics changes, metaphysics changes, too. However, this notion contradicts the general principles and main goal of classical metaphysics. Their search for immutable reality and truth is what draws metaphysicians to metaphysics. In each case, we should consider the obscurity of the relationship between metaphysics and physics.

Theology angle

Another weakness of metaphysics arises from its relationship with theology. Metaphysics was dimly interpreted first by Christians and later Muslim theologians to defend their religious beliefs, turning metaphysics into a "theology." More precisely, metaphysics entered a new phase in which it weakened for the benefit of theology. It does not matter if this was the right orientation, the point that does matter is this: When the number of criticisms toward religion increased, metaphysics also got its share; as religious thought weakened, metaphysics also weakened and eventually lost its power. And today, it is discussed whether metaphysics based on a new understanding of science is possible. Since metaphysics was built upon science in the past, it is possible to create a new metaphysics based on a new understanding of science! This apparently reasonable argument would mean nothing to classical metaphysics. We can explain this in a few ways.

Above all, a science named "after physics" does not require a compulsory relationship between metaphysics and natural sciences. Nonetheless, it is obvious that there are some serious problems with this. Even some of them were mentioned by Muslim polymath Ghazali and criticized firmly in his "Incoherence of the Philosophers." That is not the point, so we will not further this discussion, but it is important to remember that metaphysics has never accepted such an obligation. Muslim philosophers and Sufis never associated a commitment to the systematic relationship between natural sciences and metaphysics and neither did they acknowledge metaphysics as a science that borrowed a method. Muslim scholar Ibn Arabi expressed this notion loud and clear by coining the expression "making metaphysics without physics(nature)." Undoubtedly, this notion does not represent the ideas of Muslim philosophers. However, it can make us approach the assumed relationship between natural sciences and metaphysics with suspicion. According to them, one of the primary missions, maybe the second mission of metaphysics, is to categorize and certify the methods of sciences. When this mission is accounted for along with the first mission of metaphysics, which is to prove the existence of God, metaphysics separates not only from natural sciences but also from logic and reaches a level of absolute certainty. Even though Ibn Arabi broke this connection off at first, he later accepted that metaphysics could categorize the sciences; the authentic knowledge and understanding of being could be rebuilt through metaphysics that separated from "nature."

If metaphysics is not dependent on the methods of particular sciences, then what is its method? It is obviously a method different from the ways of natural sciences. But the obscurity here is the weakness of metaphysics against the criticisms. It has never stated clearly what its process is. Some complaints against metaphysics feed on this obscurity, as we see in the criticism of Ibn Khaldun when he described it as "a science peculiar to people who have special abilities." Metaphysics lacks a method similar to natural sciences that research an aspect of being as it does not analyze being from a single aspect. Then what is its method? Does Ibn Arabi’s idea of "metaphysics without nature" imply that there can be no method? If so, how can it distinguish the wrong from the right? And most importantly, how can metaphysical knowledge be distinguished from rhetoric or sophistry?

How to acquire

There are some arguments explaining how metaphysical knowledge is acquired and they are also the aspects that determine the metaphysical understanding of Sufis. Sufis also put forward another aspect that made them separate from philosophers – according to Sufis, the Prophet Muhammad himself rendered metaphysical knowledge authentic and confident. In other words, the witness of the prophet, who had seen the absolute reality, was the actual testimony of metaphysical knowledge. There is no doubt that this point is distinctive for Sufis. And yet they accepted some of the references of philosophers about the process of attaining knowledge. The most important one is that a human has an "intelligent" spirit. The most indispensable principle of metaphysics is the idea of having an intelligent spirit or soul. Most of the misunderstandings about metaphysical thinking stem from the misusage of the term "intelligent," as it has a very different connotation in the daily language. "An intelligent soul" means that the soul can "think" free of any tool or data and in this sense, this expression refers to "separate intelligences."

We can make two deductions here: First, an intelligent soul has evident principles. We can think of these principles as "direct data." A soul can attain metaphysical knowledge directly from these data, which have no connection with sense perception. In such cases, what do natural sciences serve? Because when philosophy categorizes the sciences as logic, nature or mathematics, a process of perfection is also implied by that. There is undoubtedly a ranking between sciences and this ranking is the evidence for this process. And maybe that is why there is a misconception about metaphysics being dependent on natural sciences. Classical metaphysics provides this solution: Natural sciences are like "stimulus" or "preliminary" for the soul. In other words, natural sciences prepare the soul to get "intelligent." The critical question here is the relation of "the intelligent soul" with the body and this question occupied the minds of both Sufis and philosophers. This is a very controversial subject with so many details we cannot mention here, so it would be enough to state this: Muslim philosophers never had a theory on soul-body dualism as Descartes did. They drew a line between soul and body and this distinction later served to their argument about the distinction of natural sciences and metaphysics. Even though the soul dwells in the body, it is also distinct from the body in an inexplicable way. The act of this intelligent soul is "to reason." The knowledge acquired from the reasoning of this soul determines and legitimizes the methods and understanding of the natural sciences. We can now talk about metaphysics free from nature. However, speaking of natural sciences or authentic learning without any reference to metaphysics is impossible.

The function of intelligence in metaphysics differs from the "reasoning" that theologians – especially the Mu’tazilites – regard as the source of rational knowledge. This is where Sufis separated from theologians and approached metaphysicians: intellection and isolation are the same and differ from reasoning. The soul reaches metaphysical knowledge through isolation. In this process, one breaks all their relations from the sensible world; at that point, sensible knowledge is meaningless. Autodidactic works of Muslim philosophers aim to research whether this knowledge is possible. Sufis wondered about it, too and asked whether it is possible to reach the understanding of reality without studying logic or philosophy and gave a positive answer. Either way, Sufis and philosophers accept that it is possible to acquire metaphysical knowledge through the isolation of the soul. The key concepts are "evident knowledge" and the intelligent soul.

These arguments that philosophers put forward gave Sufis vast opportunities. Ibn Arabi, for example, tells us stories about how illiterate people can reach authentic knowledge. He explains this process as "reaching authentic knowledge without the help of natural sciences." If this notion is true, then discussing whether metaphysics changes as physics does is pointless. This is a topic for another article.