Descartes' Philosophy: Doubt and Divine Proofs

Descartes' Methodological Doubt

Descartes' methodological doubt reflects a pivotal historical movement, aiming to establish a process for discovering the first indubitable truth. He presents a situation of crisis and disorientation in the pursuit of knowledge.

There are two key moments in this process:

• Negative Moment: Suspending judgment on anything that can be doubted.
• Positive Moment: The consequence of this doubt is the discovery of the first true and certain knowledge.

Central to this process are several hypotheses of doubt:

• The Senses Hypothesis: Our senses sometimes deceive us, making them unreliable sources of knowledge.
• The Dream Hypothesis: It's possible that everything we believe to be real is merely a dream.

These first two hypotheses primarily affect empirical knowledge and the sciences that rely on sensory experience. With these, Descartes casts doubt on sensitive knowledge and, consequently, the empirical sciences. However, mathematics remains untouched, as it deals with ideas and not whether external reality truly corresponds to them (e.g., 2 + 2 = 4 holds true even in a dream).

Descartes then introduces another, more radical hypothesis: The Evil Genius or Deceiving God Hypothesis. This posits the possibility of an all-powerful, malicious entity constantly deceiving us, even about seemingly certain truths like mathematical principles.

At this point, there is no choice but to continue searching for that first, undeniable piece of evidence, as even mathematics now seems unreliable. Descartes must pursue his method to its conclusion if he wishes to build a safe and indubitable foundation for knowledge. Up to this point, doubt is universal because everything can be questioned.

Descartes' Proofs for God's Existence

After establishing the certainty of his own existence (Cogito, ergo sum), Descartes sought to find other truths that could not be doubted. He viewed the existence of God as a truth of the mind and reason, an innate idea. To demonstrate God's existence, he presents three arguments:

• The Argument from the Cause of the Idea of God

  This argument, drawing inspiration from thinkers like St. Thomas Aquinas and St. Anselm (though distinct from their specific formulations), centers on the structure of ideas. Ideas possess objective reality, which differs from their formal reality (the reality of the idea as a mental act). The objective reality of an idea must have a cause with at least as much formal reality as the objective reality contained in the idea itself. For instance, the idea of an infinite substance (God) must have an infinite cause. Since Descartes, a finite being, cannot be the cause of an infinite idea, an infinite being (God) must exist as its cause. This idea of an infinite substance is presented as an innate, clear, and distinct idea.

• The Argument from the Cause of Res Cogitans (Thinking Substance)

  This argument complements the previous one. Descartes, as a doubting and therefore imperfect being, possesses the idea of a perfect being. If he were the cause of his own existence, he would have endowed himself with all perfections, including existence itself. Since he is imperfect and dependent, he cannot be the cause of his own existence, nor can he be the cause of the idea of perfection within him. Therefore, a perfect being, God, must be the ultimate cause of his existence and the source of the idea of perfection.

• The Ontological Argument

  Taken from St. Anselm of Canterbury (11th century), this argument proves God's existence from the very idea of God (His essence). For Descartes, a perfect being must exist. If a perfect being did not exist, it would lack existence, which is a perfection. A being lacking a perfection would not be perfectly perfect, leading to a contradiction. Therefore, a perfect being (God) necessarily exists. Descartes' ontological argument, however, faces criticisms regarding the transition from a concept in the mind to reality, and it relies on a concept of God inherited from Scholasticism without prior empirical validation.

Some interpretations suggest that Descartes' demonstrations of God's existence might appear to contradict the very premises of his method, particularly the passage from the internal world of ideas to the external world. This transition is sometimes seen as a 'jump in a vacuum,' potentially rendering the Cartesian project incomplete or a failure in its own terms.