The 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. As Descartes explained in a margin note, "we cannot doubt of our existence while we doubt." In the posthumously published The Search for Truth by Natural Light, he expressed this insight as dubito, ergo sum, vel, quod idem est, cogito, ergo sum. Antoine Léonard Thomas, in a 1765 essay in honor of Descartes presented it as dubito, ergo cogito, ergo sum.
Epistemology, or the theory of knowledge, is the branch of philosophy concerned with knowledge. Epistemology is considered a major subfield of philosophy, along with other major subfields such as ethics, logic, and metaphysics.
René Descartes was a French philosopher, scientist, and mathematician, widely considered a seminal figure in the emergence of modern philosophy and science. Mathematics was central to his method of inquiry, and he connected the previously separate fields of geometry and algebra into analytic geometry. Descartes spent much of his working life in the Dutch Republic, initially serving the Dutch States Army, later becoming a central intellectual of the Dutch Golden Age. Although he served a Protestant state and was later counted as a Deist by critics, Descartes was Roman Catholic.
In philosophy, rationalism is the epistemological view that "regards reason as the chief source and test of knowledge" or "any view appealing to reason as a source of knowledge or justification", often in contrast to other possible sources of knowledge such as (blind) faith, tradition, or sensory experience. More formally, rationalism is defined as a methodology or a theory "in which the criterion of truth is not sensory but intellectual and deductive".
Solipsism is the philosophical idea that only one's mind is sure to exist. As an epistemological position, solipsism holds that knowledge of anything outside one's own mind is unsure; the external world and other minds cannot be known and might not exist outside the mind.
Nicolas Malebranche was a French Oratorian Catholic priest and rationalist philosopher. In his works, he sought to synthesize the thought of St. Augustine and Descartes, in order to demonstrate the active role of God in every aspect of the world. Malebranche is best known for his doctrines of vision in God, occasionalism and ontologism.
Discourse on the Method of Rightly Conducting One's Reason and of Seeking Truth in the Sciences is a philosophical and autobiographical treatise published by René Descartes in 1637. It is best known as the source of the famous quotation "Je pense, donc je suis", which occurs in Part IV of the work. A similar argument, without this precise wording, is found in Meditations on First Philosophy (1641), and a Latin version of the same statement Cogito, ergo sum is found in Principles of Philosophy (1644).
Philosophical skepticism is a family of philosophical views that question the possibility of knowledge. It differs from other forms of skepticism in that it even rejects very plausible knowledge claims that belong to basic common sense. Philosophical skeptics are often classified into two general categories: Those who deny all possibility of knowledge, and those who advocate for the suspension of judgment due to the inadequacy of evidence. This distinction is modeled after the differences between the Academic skeptics and the Pyrrhonian skeptics in ancient Greek philosophy. In the latter sense, skepticism is understood as a way of life that helps the practitioner achieve inner peace. Some types of philosophical skepticism reject all forms of knowledge while others limit this rejection to certain fields, for example, to knowledge about moral doctrines or about the external world. Some theorists criticize philosophical skepticism based on the claim that it is a self-refuting idea since its proponents seem to claim to know that there is no knowledge. Other objections focus on its implausibility and distance from regular life.
Meditations on First Philosophy, in which the existence of God and the immortality of the soul are demonstrated is a philosophical treatise by René Descartes first published in Latin in 1641. The French translation was published in 1647 as Méditations Métaphysiques. The title may contain a misreading by the printer, mistaking animae immortalitas for animae immaterialitas, as suspected by A. Baillet.
In geometry, a chiliagon or 1000-gon is a polygon with 1,000 sides. Philosophers commonly refer to chiliagons to illustrate ideas about the nature and workings of thought, meaning, and mental representation.
In the philosophy of perception and philosophy of mind, direct or naïve realism, as opposed to indirect or representational realism, are differing models that describe the nature of conscious experiences; out of the metaphysical question of whether the world we see around us is the real world itself or merely an internal perceptual copy of that world generated by our conscious experience.
Subjectivity in a philosophical context is a concept of truth that depends upon an individual's conscious experience. Generally speaking, a philosophical proposition is considered to have subjective truth when its truth conditions are met only when considering the claim from the viewpoint of a sentient being. Subjectivity has been given various and ambiguous definitions by differing sources as it is not often the focal point of philosophical discourse. However, it is related to ideas of consciousness, agency, personhood, philosophy of mind, reality, and truth. Three common definitions include that subjectivity is the quality or condition of:
Certainty is the epistemic property of beliefs which a person has no rational grounds for doubting. One standard way of defining epistemic certainty is that a belief is certain if and only if the person holding that belief could not be mistaken in holding that belief. Other common definitions of certainty involve the indubitable nature of such beliefs or define certainty as a property of those beliefs with the greatest possible justification. Certainty is closely related to knowledge, although contemporary philosophers tend to treat knowledge as having lower requirements than certainty.
Philosophical realism – usually not treated as a position of its own but as a stance towards other subject matters – is the view that a certain kind of thing has mind-independent existence, i.e. that it exists even in the absence of any mind perceiving it or that its existence is not just a mere appearance in the eye of the beholder. This includes a number of positions within epistemology and metaphysics which express that a given thing instead exists independently of knowledge, thought, or understanding. This can apply to items such as the physical world, the past and future, other minds, and the self, though may also apply less directly to things such as universals, mathematical truths, moral truths, and thought itself. However, realism may also include various positions which instead reject metaphysical treatments of reality entirely.
The Cartesian circle is an example of fallacious circular reasoning attributed to French philosopher René Descartes. He argued that the existence of God is proven by reliable perception, which is itself guaranteed by God.
The trademark argument is an a priori argument for the existence of God developed by French philosopher and mathematician, René Descartes. The name derives from the fact that the idea of God existing in each person "is the trademark, hallmark or stamp of their divine creator".
Cartesianism is the philosophical and scientific system of René Descartes and its subsequent development by other seventeenth century thinkers, most notably François Poullain de la Barre, Nicolas Malebranche and Baruch Spinoza. Descartes is often regarded as the first thinker to emphasize the use of reason to develop the natural sciences. For him, philosophy was a thinking system that embodied all knowledge.
Cartesian doubt is a form of methodological skepticism associated with the writings and methodology of René Descartes. Cartesian doubt is also known as Cartesian skepticism, methodic doubt, methodological skepticism, universal doubt, systematic doubt, or hyperbolic doubt.
A proof is sufficient evidence or a sufficient argument for the truth of a proposition.
In philosophy, a point of view is a specific attitude or manner through which a person thinks about something. This figurative usage of the expression dates back to 1760. In this meaning, the usage is synonymous with one of the meanings of the term perspective.
