Gottlob Frege did not call any of his philosophical views by the name “ontology”, let alone “metaontology”. When applied to Frege’s thought, the term “metaontology” is clearly anachronistic. Still, this paper discusses two philosophical positions that Frege held and that have metaontological relevance. They are the doctrine of the ambiguity of the word “is” and the doctrine of three realms. It is well known that Frege regarded existence as a second-order concept. Likewise, Frege’s distinction between three realms has been studied in detail. However, the relation between the two doctrines has not been clarified in detail; instead, they are studied as separate themes that occur in Frege’s writings. It is true Frege does not combine the two topics. This paper seeks to show that the two doctrines are connected in an interesting way: The concept of existence that is expressed as a second-order concept in the formula language plays an important logical role, while the doctrine of three realms is a means to express a division between three modes of being or three ways to exist. It seeks to show that the modes of being are predicated of objects, but they have a special, constitutive role in relation to those entities of which they are predicated. The word “exist” is thus an analogous rather than a completely ambiguous word. The paper suggests that Frege's views on of “being” and being contain elements both of Aristotelian and of Kantian approaches to metaphysics.

The article serves as an introduction to the newly published Finnish translation of Martin Heidegger’s Introduction to Metaphysics. I first discuss the respective historical situations in which these lectures were originally delivered (1935) and first published (1953), arguing that they can be read as an indirect account of Heidegger’s relationship to National Socialism after his rectorate (1933–34), and also as a contemporary document of the possibilities and necessities of philosophizing under the Third Reich. I then delineate the central importance of these lectures as signaling the “reversal” (Kehre) undertaken by Heidegger’s thinking after Being and Time (1927) and concluding in a programmatic outline of the central questions of Heidegger’s later thought.

Derrida's deconstructive strategy of reading texts can be understood as a way of highlighting the irreducible plurality of discursive meaning that undermines the traditional Western “logocentric“ desire for an absolute point of reference. While his notion of logocentrism was modeled on Heidegger's articulation of the traditional ontotheological framework of Aristotelian metaphysics, Derrida detects a logocentric remnant in Heidegger's own interpretation of gathering (Versammlung) as the basic movement of λόγος, discursiveness. However, I suggest that Derrida here touches upon a certain limit of deconstruction. As Derrida himself points out, the “decentering“ effect of deconstruction does not simply abolish the unifying and focalizing function of discourse. Insofar as deconstruction involves reading and interpreting, it cannot completely evade narrative focalization. Rather, both Heidegger and Derrida can be understood as addressing the radical contextuality of all discursive centers and focal points as well as the consequent impossibility of an ultimate and definitive metanarrative.

In discussion on natural kinds one of the central debates is held between monistic and pluralistic view. While monists argue that things are what they are due to their microstructure, pluralists suggest there are several equally legitimate ways to define the nature of a subject. As compounds, proteins raise questions such as "How we should define natural kinds?" and "What makes an object a member of certain kind?" This thesis examines the problems that microstructural monism faces in defining macromolecules and whether it is able to answer the counter arguments. Recently studies on microbiology have shown that some proteins are able to perform secondary tasks. This ability is called moonlighting and it has raised a need for refining the theories defining proteins. To do so, in this thesis the central problems associated with the functions of proteins are introduced. After this, the solutions offered by the contemporary discussion are considered in order to decide whether microstructural essentialism can survive from challenges set by moonlighting. This thesis is divided into three sections. The first section (the chapters one, two and three) will introduce the basic terminology, the key concepts, and will provide the frames of the discussion. In the second section (the chapters four and five) the relevant structure and properties of proteins will be examined more closely. In addition to this, the current discussion is introduced in more detail. The section three (the chapters six, seven and eight) weighs various challenges set by functionality and proposes a view according to which microstructuralism may indeed be able to answer these challenges. However, this requires remodeling of the microstructural argument and reviewing its basic assumptions. This is done by reflecting and analyzing writings of Jordan Bartol, William Goodwin and Emma Tobin, with works of Sandra Mitchell, Paul Needham, Jaap van Brakel, Raphael van Riel and Robert Van Gulick. This thesis concludes that both, microstructuralism and pluralism, have trouble in explaining the structure and dynamic nature of proteins. While pluralism offers a promising ground of explaining the complexity of proteins, it does not emphasize enough the significance of chemical structure. Compared with traditional microstructuralism and pluralism, the views of Jordan Bartol and William Goodwin are in better harmony with current scientific research and, moreover, offer a more appealing answer from the metaphysical point of view. Bartol's view requires adapting dualism of kinds, where macromolecules are classified to chemical and biological kinds. Goodwin is able to hold on to monism by allowing additional levels of explanation. This thesis concludes that Goodwin's theory therefore offers the most promising ground to build a coherent theory of macromolecules. Additionally, Goodwin's levelled microstructuralism is able to retain monism.

For Heidegger, the fundamental “rationality” of Western metaphysics lies in the fact that its “leading question” concerning beings as beings constantly refers back to the question concerning the ground (arche, ratio, Grund) of beings. Whereas metaphysics has sought to ground beings in ideal beingness, Heidegger attempts to think beingness as itself based on the withdrawing “background” dimension of no-thing-ness that grounds finite presence by differing from it. In Heidegger’s earlier work, the structure of this “grounding” is considered in terms of Dasein’s temporal transcendence; later, it is rearticulated through the fourfold dimensionality of meaningfulness (Geviert), converging in a concrete thing.