[evil demon] a dark force deceives us, making us believe false representations to be true
After having questioned the information conveyed by the senses, and then having suggested that everything we believe to be reality could be just a dream, Descartes says :
I will suppose, then, not that Deity, who is sovereignly good and the fountain of truth, but that some malignant demon, who is at once exceedingly potent and deceitful, has employed all his artifice to deceive me; I will suppose that the sky, the air, the earth, colors, figures, sounds, and all external things, are nothing better than the illusions of dreams, by means of which this being has laid snares for my credulity; I will consider myself as without hands, eyes, flesh, blood, or any of the senses, and as falsely believing that I am possessed of these; I will continue resolutely fixed in this belief, and if indeed by this means it be not in my power to arrive at the knowledge of truth, I shall at least do what is in my power, to suspend my judgment.
In spite of its power, the evil demon postulated by Descartes does not have the power to make him doubt its existence. The evidence of the cogito is so strong that this hypothesis cannot challenge it. Beyond the intuitive certainty of the cogito, Descartes' argument consists in saying that if an evil genius deceives him, he himself must be deceived.
Then without doubt I exist also if he deceives me, and let him deceive me as much as he will, he can never cause me to be nothing so long as I think that I am something.
Be the change that you want to see in the world.
Simplicity, patience, compassion.
These three are your greatest treasures.
Simple in actions and thoughts, you return to the source of being.
Patient with both friends and enemies,
you accord with the way things are.
Compassionate toward yourself,
you reconcile all beings in the world.
Cultivate your intelligence, dear students, but also take care that it does not subordinate itself to everything else, and that the accessory does not become the main one. May your heart not be the fool of your mind. Pascal said: "The heart has its reasons of which reason knows nothing"; yet this deep word is not of absolute accuracy. For if the heart has its reasons, Reason knows them and recognizes itself in them.
The whole work of Reason consists in subordinating Intelligence to the Heart.
What is demanded of man is not, as some existential philosophers teach, to endure the meaninglessness of life, but rather to bear his incapacity to grasp the unconditional meaningfulness of life in rational terms.