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Philosophical Works · Chapter

XXI explained

Descartes argues that the duration of our life alone demonstrates the existence of God, because the parts of time are independent and non-coexistent, so our continued existence requires a cause that continually reproduces or conserves us.

What happens

Descartes argues that the duration of our life alone demonstrates the existence of God, because the parts of time are independent and non-coexistent, so our continued existence requires a cause that continually reproduces or conserves us. Since we lack the power to conserve ourselves, that cause must be self-conserving and is God.

Themes in this chapter

  • Existence of God

    Descartes presents a proof of God's existence based on the need for a conserving cause for our continued existence.

  • Reason and Method

    The argument uses a rational analysis of the nature of time and causation to demonstrate a metaphysical truth.

Characters to notice

  • Narrator

    Presents the argument that the duration of life proves God's existence.

  • God

    Identified as the self-conserving being who continually conserves us.

Key passages

  • the duration alone of our life is sufficient to demonstrate the existence of God

    The mere fact that we continue to exist over time proves that God exists.

    This is the central claim of the chapter.

  • its parts are not mutually dependent, and never coexistent; and, accordingly, from the fact that we now are, it does not necessarily follow that we shall be a moment afterwards, unless some cause, viz., that which first produced us, shall, as it were, continually reproduce us, that is, conserve us.

    The parts of time are independent and do not coexist, so our present existence does not guarantee our existence a moment later unless a cause—the same one that first created us—continuously recreates or preserves us.

    Descartes explains why continuous conservation is necessary.