Martin HeideggerMartin Heidegger (ˈhaɪdɛɡər,_ˈhaɪdɪɡər; ˈmaʁtiːn ˈhaɪdɛɡɐ; 26 September 1889 26 May 1976) was a German philosopher who is best known for contributions to phenomenology, hermeneutics, and existentialism. He is among the most important and influential philosophers of the 20th century. He has been widely criticized for supporting the Nazi Party after his election as rector at the University of Freiburg in 1933, and there has been controversy about the relationship between his philosophy and Nazism.
Substance theorySubstance theory, or substance–attribute theory, is an ontological theory positing that objects are constituted each by a substance and properties borne by the substance but distinct from it. In this role, a substance can be referred to as a substratum or a thing-in-itself. Substances are particulars that are ontologically independent: they are able to exist all by themselves. Another defining feature often attributed to substances is their ability to undergo changes. Changes involve something existing before, during and after the change.
ExistentialismExistentialism is a form of philosophical inquiry that explores the issue of human existence. Existentialist philosophers explore questions related to the meaning, purpose, and value of human existence. Common concepts in existentialist thought include existential crisis, dread, and anxiety in the face of an absurd world, as well as authenticity, courage, and virtue. Existentialism is associated with several 19th- and 20th-century European philosophers who shared an emphasis on the human subject, despite often profound differences in thought.
Cogito, ergo sumThe Latin cogito, ergo sum, usually translated into English as "I think, therefore I am", is the "first principle" of René Descartes's philosophy. He originally published it in French as je pense, donc je suis in his 1637 Discourse on the Method, so as to reach a wider audience than Latin would have allowed. It later appeared in Latin in his Principles of Philosophy, and a similar phrase also featured prominently in his Meditations on First Philosophy. The dictum is also sometimes referred to as the cogito.
Phenomenology (philosophy)Phenomenology is the philosophical study of objectivity – and reality more generally – as subjectively lived and experienced. It seeks to investigate the universal features of consciousness while avoiding assumptions about the external world, aiming to describe phenomena as they appear to the subject, and to explore the meaning and significance of the lived experiences.
OntologyIn metaphysics, ontology is the philosophical study of being, as well as related concepts such as existence, becoming, and reality. Ontology addresses questions like how entities are grouped into and which of these entities exist on the most fundamental level. Ontologists often try to determine what the categories or highest kinds are and how they form a system of categories that encompasses the classification of all entities. Commonly proposed categories include substances, properties, relations, states of affairs, and events.
