Knowledge has the form of a tree, and since metaphysics is…

Metaphysics is the study of the most general nature and basic structure of reality, and therefore the concepts of metaphysics, concepts like time, space,…

— Gonzalo Rodriguez-Pereyra

That Hegel is a metaphysician, and that he thinks metaphysics is fundamental to philosophy, is plain enough from his definition of philosophy.

— Frederick C. Beiser

“The purpose of this critique of pure speculative reason consists in the attempt to change the old procedure of metaphysics, and to bring about…

— Immanuel Kant

The role of metaphysics in relation to other disciplines, whether philosophical or not and including the natural sciences, is thus a foundational role. Lack…

— Gonzalo Rodriguez-Pereyra

If the aim of physical theories is to explain experimental laws, theoretical physics is not an autonomous science; it is subordinate to metaphysics.

— Pierre Duhem

Those who take knowledge to be a whole zoo of sub-disciplines will react to my giving metaphysics a privileged position in that zoo or…

— Gonzalo Rodriguez-Pereyra

Those who think that metaphysics is just misunderstood grammar will react to my giving metaphysics some place or another in the system of knowledge.

— Gonzalo Rodriguez-Pereyra

It has long been my personal view that the separation of practical and theoretical work is artificial and injurious. Much of the practical work…

— Christopher Strachey

Kantian ethical theory distinguishes three levels: First, that of a fundamental principle (the categorical imperative, formulated in three main ways in Kant's Groundwork); second,…

— Allen W. Wood

The classes of problems which are respectively known and not known to have good algorithms are of great theoretical interest. [...] I conjecture that…

— Jack Edmonds

A theoretical system does not merely state facts which have been observed and that logically deducible relations to other facts which have also been…

— Talcott Parsons

The trouble is that when you read criticisms about the other films that I've made you get the impression that they're all about themes,…

— Michael Haneke

The fear of speculation, the ostensible rush from the theoretical to the practical, brings about the same shallowness in action that it does in…

— Friedrich Wilhelm Joseph Schelling

The pace of science forces the pace of technique. Theoretical physics forces atomic energy on us; the successful production of the fission bomb forces…

— Erich Fromm

Close contact between science and the practice of collective farms and State farms creates inexhaustible opportunities for the development of theoretical knowledge, enabling us…

— Trofim Lysenko