What are the main characteristics and works of Renato Descartes, John Locke, Immanuel Kant, Federico Hegel, Arthur Schopenhauer, Augusto Comte, and Carlos Marx?

Renato Descartes was a French philosopher and mathematician who rejected scholastic teachings and became the Father of Rationalism. He used the geometric method and applied the methodical doubt to find the first principle of human knowledge. He began by doubting the reality of the physical, mathematical, and metaphysical environment, but when he tried to doubt everything, he realized that he could not doubt his own doubt. For him, doubting is thinking, so he said: 'I think, therefore I am' (Cogito, ergo sum). His works include Discourse on the Method, Meditations on First Philosophy, Principles of Philosophy, and Treatise on the Passions of the Soul.
John Locke rejected the existence of innate ideas and affirmed that knowledge comes from experience. He distinguished three kinds of knowledge: intuitive, demonstrative, and sensitive. His works include An Essay Concerning Human Understanding, Thoughts on Education, among others.
Immanuel Kant founded Classical German Idealism. His thought is called Criticism, Transcendental Idealism, and Agnosticism. His fundamental thesis is that man creates the truth of the things he knows. For Kant, ideas and thought have primacy over objects (idealism). He says that we cannot know the intimate nature of things, what we know are the phenomena of things and not things in themselves (agnosticism). His works include Critique of Pure Reason, which deals with the problem of knowledge; Critique of Practical Reason, which deals with the ethical or moral problem; and Critique of Judgment, which deals with the aesthetic or art problem.
Federico Hegel considers that the idea or spirit is the only existing reality, everything else is just a phenomenon derived from this Idea. Material nature is only its exteriorization. He considers that all reality changes dialectically according to the triad: thesis, antithesis, and synthesis. The Hegelian system considers Logic as thesis, the philosophy of nature as antithesis, and the philosophy of spirit as synthesis. His works include Phenomenology of Spirit, Science of Logic, Philosophy of Right, Lessons on the History of Philosophy, among others.
Arthur Schopenhauer is the distinguished representative of Voluntarism. In his book 'The World as Will and Representation', he argues that everything is informed by the will, the eternal desire to be and to live, everything else being pure appearance, pure becoming. Reality is will, permanent desire implies dissatisfaction, will is permanent pain. His philosophy is considered pessimistic.
Augusto Comte held that knowledge must be limited to sensible facts. Positive knowledge is knowledge of observed facts; Positive knowledge is what can be subjected to empirical proof, and the only basic knowledge is scientific knowledge. Comte affirmed that each of our main conceptions, each branch of our knowledge necessarily passes through three different theoretical stages: the theological or fictitious stage, the metaphysical or abstract stage, and the scientific or positive stage. He represents Positivism and is the father of Sociology. His works include Course of Positive Philosophy, Discourse on the Positive Spirit, and System of Positive Politics.
Carlos Marx is the founder of Scientific Socialism. He conceives Philosophy as a praxis to make the revolution, to transform society into an earthly paradise, establishing the dictatorship of the proletariat as a means to reach Communism. He represents Dialectical Materialism (Philosophical Foundations of Marxism) and Historical Materialism (explains the evolution of society through economic and social factors). His works include The Communist Manifesto, Capital, and The German Ideology.