Metaphysics The Foundational Science

In a strong sense, metaphysics is really at the heart of philosophy since it deals with the nature of reality in its widest throw. Metaphysics comprises two main areas or sub-disciplines ontology and transcendental metaphysics. Ontology concerns itself with responding to the question what exists while Transcendental Metaphysics concerns itself with the questions what is it for something to exist , are there different modes of existence , and if there are different modes of existence, what are the truth makers for these modes  

More specifically, ontology attempts to formulate a complete list of the fundamental categories of being, while transcendental metaphysics concerns itself with (a) a fundamental understanding of essence, existence, nature, cause, etc., and the relationships between them, (b) the truth makers for modal claims, and (c) the transcendental attributes of being—attributes which apply to all beings simply as beings. 

An example of this philosophical approach is shoes. What is common or universal to all shoes cannot be drawn or imagined. As such, there is absolutely nothing which can be sensed—and hence measured—about shoeness. When one has an idea (not image ) of what is common to all shoes, of every shape, size, color, style, etc., one has grasped conceptually the form (formal cause— the whatness )— the shoeness. 

metaphysics is the foundational philosophical discipline—quite literally the foundational science. Whereas the modern empirical sciences (MESs) are the most fundamental form of knowledge because their objects are accessible through the senses, the MESs are neither the only form of knowledge nor the most important. All the particular (individual) sciences—including the productive sciences such as medicine and engineering and architecture—depend upon metaphysics for their ultimate presuppositions and basic principles. The particular sciences seek to understand their particu- 

According to Aristotle, motion must be defined as the act [entelechy] of that which exists in potency insofar as it is such actus existentis in potentia secundum quod huiusmodi) Physics 3.2, 201a27-29). 

---