Cartesian Philosophy: Key Concepts and Definitions

Alma (Soul)

A finite spiritual substance. It is simple because it is not composed of parts and therefore immortal. It is an independent substance from the body and does not require it to exist. It is the principle of consciousness, that is, what makes us aware.

Certainty

An act of perfect understanding that fully recognizes the clarity, distinction, and conviction of truth. It is the security of possessing the truth. It is based on evidence. It refers to the evidence that something is true, as false certainty can exist: being sure of something that is actually wrong.

Clarity and Distinction

These belong to the first rule of the Cartesian method and are key features of evidence. Claro is what is transparent, clear, and visible to reason. Distinto is differentiated and unmistakable. Only clear and distinct ideas are true.

Body

Substancia extensa. It is a material substance, limited by shape, occupies space, and can be weighed and measured. Its operation resembles a machine, being composed of material parts that move the whole. The body is finite, limited, and mortal.

God

Substancia infinita. The infinite Being who has placed the idea of infinity in my mind. His presence demonstrates His existence. He possesses all perfections and cannot lack the perfection of existence. He is omnipotent and good, and His primordial attribute is truth.

Doubt

The starting point of Cartesian philosophy. It is an attitude of prevention of the mind towards unknown knowledge, both theoretical and practical. It is methodical, not skeptical, and it applies to universal truth. It covers the senses, dreams, the evil genius, and bad actions. It does not apply to faith.

Extension

Everything material, sensible, or corporeal with width, height, and depth. It is the essential attribute of the world. The extended does not think, and thinking is not extended. It is mathematizable. This substance can be calculated, measured, and framed in space due to limited Cartesian coordinates. It is finite and mortal.

Man

The accidental union of two substances: thought (alma) and extension (body). Soul and body are separate substances, but connected through the pineal gland (dualism). Man is like a thinking machine.

Idea

Pensamiento. Any object of thought. There are three types of ideas: adventitious (transient), factitious (from imagination), and innate (present from birth).

Method

A set of ordered, certain, and safe rules to avoid error and gain real knowledge. It is the way to reach the truth and a useful tool to discover new truths. It consists of four rules: evidence, analysis, synthesis, and enumeration.

World

The world is an extended substance, a finite material reality. It is an unthinking, corporeal, and geometric extension that is mathematizable. It is like a great machine composed of smaller machines. The created world exists because God is truthful and does not deceive. It is an innate idea.

Thinking

An act of consciousness, what makes us conscious. Understanding, doubting, imagining, etc., occur in the thinking substance (soul). There is nothing in thought that does not come from thought.

Reason

The faculty to try and distinguish truth from falsehood. It is paramount in humans with good use of its natural light. It is the basis of rationalism; knowledge is based on reason. Therefore, Descartes distrusts the senses.

Substance

That which does not need anything else to exist or be supported. It is the species of things in which properties and qualities occur. Descartes distinguishes three: thinking, infinite, and extended.

Truth

Objective in Cartesian philosophy. It is understood as certainty and as evidence of true judgment. It involves understanding and will. In discovering the first truth, Descartes rejects skepticism.

Me (I)

The first innate, clear, and distinct idea for Descartes. This evidence is the subject of my thoughts. It supposes the discovery of the thinking self: "I think, therefore I am."