PHIL 101 Lecture Notes - Lecture 11: Cogito Ergo Sum, Actual Infinity
Descartes’ Meditations
Med 1: Radical Doubt
● All skeptical arguments are brought to the table
● Doesn it follow that I don’t exist?
● No, I must exist, if it is me who is convinced of something
● Creator who deceives
● I must exist to be deceived
● He can never make it the case that I am nothing if I think I am something
● “I am, I exist” must be true, necessarily exist through thought
● Truth beyond all rational doubt
● Begins with Descartes doubting/thinking, from this he gets “I exist”
● Cogito Ergo Sum - I think, therefore I am
● I am - the fundamental truth
Med. 2: I exist (sum)
Refuting/establishing truths no rational person can doubt
The Inferential Interpretation
● Inferring, deducing, from “I think or doubt” that I exist
● In order to infer something you need a proposition (truth claim)
● Proposition “I think/doubt”, infer “I exist”
● Propositions can be either true or false
● If the first proposition is true, the second proposition must also be true
● If I can truly doubt, then it must follow that I exist
● Inference is a truth preserving relation between propositions
● If you accept this interpretation, if you take this to be the first truth in Descartes’ situation,
Descartes must presuppose another truth
● I think must be the first truth, though Descartes says I exist is the first truth
● It is increasingly common to accept an alternative interpretation
Performative Interpretation
● Descartes is engaging in the act of doubting or thinking
● “I doubt/think” (act)
● This act verifies the proposition “I exist”
● Not dealing with a logical inference (between propositions)
● The act renders the proposition certain
● Insofar as I am engaged in this act, this proposition is verified.
● If I cease to think/doubt, the proposition can no longer be verified.
● Is Descartes right to believe his existence beyond all doubt?
● If so, skeptics are wrong
Med. 3: God Exists
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Document Summary
All skeptical arguments are brought to the table. No, i must exist, if it is me who is convinced of something. He can never make it the case that i am nothing if i think i am something. Begins with descartes doubting/thinking, from this he gets i exist . Cogito ergo sum - i think, therefore i am. I am, i exist must be true, necessarily exist through thought. Inferring, deducing, from i think or doubt that i exist. In order to infer something you need a proposition (truth claim) Propositions can be either true or false. If the first proposition is true, the second proposition must also be true. If i can truly doubt, then it must follow that i exist. Inference is a truth preserving relation between propositions. If you accept this interpretation, if you take this to be the first truth in descartes" situation,
