R. Descartes, Meditations One and Two From: Meditations on First Philosophy, Meditations 1-2, pp.59-66 Trans. by D. Cress (Hackett Publishing Co., 19

Cogito, ergo sum

I think, therefore I am; a fundamental element of Western philosophy by Descartes.

Meditation

A contemplative practice that Descartes employed to doubt everything in order to find certain knowledge.

Evil genius

A hypothetical being proposed by Descartes that could deceive us about the existence of everything.

Indivisible

A property of the mind, as stated by Descartes, indicating that it cannot be broken down into parts.

Body

Described by Descartes as a divisible, corporeal entity that can exist apart from the mind.

Senses

The faculties through which we perceive the world, which Descartes argues can sometimes deceive us.

Certainty

The quality of being sure or confident; Descartes seeks this in his philosophical inquiries.

Raze

To completely destroy; used by Descartes when referring to his need to dismantle all previously held beliefs.

Foundations

The basic principles or ideas that serve as the groundwork of a system or belief; Descartes aims to find new foundations.

Doubt

A state of uncertainty or lack of conviction; central to Descartes' methodology in seeking truth.

True knowledge

Understanding based on certainty and indubitability as sought by Descartes; refers to knowledge that cannot be doubted.

Rational animal

A potential definition of man that Descartes considers, but ultimately finds insufficient for his inquiries about existence.

Thinking thing

The essence of what it means to be a human according to Descartes; emphasizes thought as the primary function of the mind.

Dualism

The philosophical concept of the separation between the mind and body as articulated by Descartes.

Meditation One

The first part of Descartes' philosophical work where he casts doubt on all but his own existence.

Meditation Two

The second part of Descartes' work in which he concludes that he exists because he can think.