16), "deals with things which are both separate (from matter) and immovable". In this connexion the scholastics (cf. St. Thorn., ibid.), distinguished two kinds of immaterial: (a) immaterial quoad esse or im- material beings, such as God and the human soul, which exist without matter; (b) immaterial guoadcon- ceptum, or concepts, such as substance, cause, quality, into the comprehension of which matter does not enter. Metaphysics, in so far as it treats of immaterial beings, is called special metaphysics and is divided into rational psychology, which treats of the human soul, rational theology, which treats of the existence and attributes of God, and cosmology, which treats of the ultimate principles of the universe. Metaphysics, in so far as it treats of immaterial concepts, of those general notions in which matter is not included, is called general metaphysics, or ontology, that is, the science of Being. Taking the term now in its widest sense, so as to include both general and special meta- physics, when we say that metaphysics is the science of the immaterial, we mean that whatever exists, whether it is an immaterial being or a material being, so long as it offers to our consideration immaterial con- cepts, such as substance or cause, is the object of metaphysical investigation. In this way, it becomes evident that this definition coincides with that given in the preceding paragraph.
(.3) Metaphysics is the science of the most abstract con- ceptions. — AH science, according to the scholastics, deals with the abstract. The knowledge of the con- crete iinlividual objects of our experience, with their ever changing qualities and the particular individu- ating characteristics which make them to be individual (for instance, the knowledge of this tree, of that flower, of this particular animal or person) may be very useful knowledge, but it is not scientific. Scien- tific knowledge begins, when we abstract from what makes the thing to be individual, when we know it in the general principles that constitute it. The first de- gree of abstraction is found in the physical sciences, which abstract merely from the particularizing, indi- viduating characteristics, and consider the general laws, or principles, of motion, light, heat, substantial change, etc. The mathematical sciences ascend higher in the scale of abstraction. They leave out of consideration not only the individuating qualities but also the physical qualities of things, and consider only quantity and its laws. The metaphysical sciences reach the highest point of abstraction. They pre- scind, or abstract, not only from those qualities which physics and mathematics abstract from, but also leave out of consideration the determination of quan- tity. They consider only Being and its highest deter- minations, such as substance, cause, quality, action, etc. "There is a science", says Aristotle (Met. IV, 1003 a, 21) " which investigates being as being, and the attributes which belong to this in virtue of its own na- ture" (rd TouTifi uTrdpxo^ra Kofl' aiirb). The objection therefore, that metaphysics is an abstract science, would, in the estimation of the scholastics, militate not only against metaphysics but against all the other sciences as well. The peculiarity of metaphysics is not that it is abstract, but that it carries the process of abstraction farther than do the other sciences. ' This, however, does not make it to be unreal. On the con- trary, what is left out of consideration in metaphysics, namely individuating qualities, physical movement, and specific cpiantity, derive whatever reality they have as conceptions from the concept. Being, which is the object of metaphysics. Metaphysics, in fact, is the most real of all the sciences precisely because, by ?.bstracting from everything else, it has centred, so to speak, its thought on Being, which is the source and root of reality everywhere else in the other sciences.
(4) Metaphysics is the science of the most universal conceptions. — This would follow from the considera-
tion offered in the preceding paragraph because, by a well known law of logic, the less the comprehension the greater the extension of a term or concept. The science which deals with the most abstract concep- tions must, therefore, be the science of the most uni- versal conceptions. Among our ideas the most uni- versal are Being, and the determinations of it wliich are called transcendental, namely unity, truth, good- ness, and beauty, each of which is coextensive with be- ing itself, according to the formulas, " Every being is one ", " Every being is true ", etc. Next in universal- ity come the highest determinations of Being in the suprema genera, substance and accident, or, if Being be analyzed in the order of metaphysical constitution, es- sence and existence, potency and actuality. Very high up in the scale of extension will be cause and effect. All these are included within the range of metaphysical inquiry, and are dealt with in every scholastic manual of metaphysics. " Being in its high- est determinations" is, then, another way of describ- ing the object of metaphysics. Where, however, shall we draw the line? What determinations are not highest? For instance, are space and time determina- tions of Being, which are general enough to be consid- ered in metaphysics? The answer to these questions is to be decided according to the dictates of practical convenience. Many of the problems sometimes in- cluded in general metaphysics may conveniently be treated in special parts, such as cosmology and psy- chology.
(5) Metaphysics is the science of the first principles. — This definition also is given by Aristotle (Met. IV, 1003 a, 26). Every science is an inquiry into the causes and principles of things; this science inquires into the first principles and highest causes, not only in the order of existence, but also in the order of thought. It belongs, then, to metaphysics (1) to inquire into the nature of cause and principle in general and to deter- mine the meaning of the different kinds of causality, formal, material, efficient, and final: (2) to investigate the first principles in the order of knowledge, and establish the validity, for instance, of the principles of identity and contradiction.
All these definitions are expressions of the Aristote- lian doctrine that metaphysics, like physics and mathe- matics, is a science of reality, it being beyond the scope of metaphysics to inquire whether reality is, or is not, given in experience. This question, which is a fundamentally important one in modern philosophy, was discussed by the scholastics in that portion of logic which they called critica, major logic, or applied logic, but which is now generally called epistemology (see Logic). Nowadays, however, the epistemo- logical problem, by a fatal mistake of method, is as- signed to metaphysics, and the result is a confusion be- tween the two branches of philosophj', viz. metaphysics and epistemology. In works like Fullerton's "Sys- tem of Metaphysics" (New York, 1906) and Hodg- son's "Metaphysics of Experience" (London, 1898) no attempt is made to separate the two.
III. The Rejection op Metaphysics, by many schools of philosophy in modern times, is one of the most remarkable developments of post-Cartesian plii- losophy. A difference in the point of view leads to a very great divergence in the estimate placed on meta- physical studies. On the one side we have the verdict that metaphysics is nothing but "transcendental moon.shine", on the other, the opinion that it is "or- ganized common sense", or "an unusually obstinate etTort to think accurately". Materialism, naturally, objects to the claim of metaphysics to be a science of the immaterial. If nothing exists except matter, a science of the immaterial has no justification. Mate- rialists, however, forget that the assertion, " Nothing exists except matter", is either a summing up of the individual experience of the materialist himself, mean- ing that he has never experienced anything except