René Descartes - Meditations

Experiences during sleep can be deceptive and seem as real as waking experiences

Concepts related to the existence of a deity and the belief that God could manipulate perception.

Latin for “I think, therefore I am,” a fundamental philosophical concept introduced by Descartes. Meaning the only “real” thing that Descartes can be certain of is that his exsistence is proven by him being able to think.

A philosophical example used by Descartes to illustrate the nature of perception and reality, typically involving the properties of wax. Even though the properties of wax change the entire perception and sensory experience of wax, it still remains the same wax with the same essence.

The branch of metaphysics concerned with the nature of being and existence.

Evil demon advocates the doubting of all things that cannot be justified through logic. He reasons that a demon intent on deceiving could easily make it appear to Descartes that he is sitting by the fire, even if this was not the case. If Descartes’ sensory experience of sitting by the fire could be caused by an evil demon, Descartes does not know that he is sitting by the fire.

All of our thoughts (true or false) are formed (or stems from something real) Even people with the most creative imagination can never imagine something with no grounding in reality.

e.g. A square will always have 4 sides. This cannot be suspected as being false or having any uncertainty