Descartes

"Several years have now passed since I first realized how numerous were the false opinions that in my youth I had taken to be true, and thus how doubtful were all those I had subsequently built upon them." (pp.1)

The First Meditation opens with Renee Descartes reflecting on all the things that he has been mistaken about, and all his beliefs that were built on those false ones. As a result, he somehow feels the need to reexamine everything he has believed in the past, and has set aside some time in front of the fireplace to do it. Renee Descartes claims him self to be "The Meditator" and decides that in order to determine truth from falsity he should declare something false if there is any reason at all for doubt. "For this reason it will suffice for the rejection of all these opinions, if I find in each of them some reason for doubt." So with this in mind, Descartes attempts to probe everything skeptically. "Nor therefore need I survey each opinion individually, a task that would be endless. Rather, because undermining the foundations will cause whatever has been built upon them to crumble of its own accord, I will attack straightaway these principles which supported everything I once believed." He realizes that everything he has come to believe has been a result of his senses telling him that something exists. "Surely whatever I had admitted until now as most true I received either from the senses or through the senses. However, I have noticed that the senses are sometimes deceptive." But the senses, like the senses of insane people, can deceive you, as can dreams. There are "no definitive signs by which to distinguish being awake from being asleep".

Descartes then decides to assume that he is sleeping. "Let us assume then, for the sake of argument that we are dreaming and that such particulars as these are not true: that we are opening our eyes, moving our head, and extending our hands. Perhaps we do not have such hands or any body at all." He reasons that we could just be dreaming and that there is no real way to tell the dreaming world from reality. "This would all be well and good, were I not a man who is accustomed to sleeping at night, and to experiencing in my dreams the very same things, or now and then even less plausible ones, as these insane people do when they are awake. How often does my evening slumber persuade me of such ordinary things as these: that I am here, clothed in my dressing gown, seated next in the fireplace-when in fact I am lying undressed in bed!" He then goes on to say that even if he is dreaming there are some things in life that are the same whether you are dreaming or not. Thus, because we cannot distinguish between the two, those simple things that remain the same are constants. He argues that dreams are like the pictures of painters and that painter's paint with some basis of truth. "For indeed when painters themselves wish to wish to represent sirens and satyrs by means of especially bizarre forms, they certainly can not assign them to utterly new natures. Rather, they simply fuse together the members of various animals. Or if perhaps they concoct something so utterly novel that nothing like it has ever been seen before (and thus is something utterly fictitious and false), yet certainly at which the very least the colors which they fasten it from must be true." They may fuse together different parts of bodies or images, but the simple parts, such as shape, quantity, and size, are in essence real or at least derived from real things. So he reasons that more tangible ideas (like physics, astronomy, and medicine) are formed by simpler ideas (arithmetic and geometry) and can be deceptive. "Thus it is not improper to conclude from this that physics, astronomy, medicine, and all the other disciplines that are dependent upon the consideration of composite things are doubtful, and that, on the other hand, arithmetic, geometry, and other such disciplines, which treat of nothing but the simplest and most general things and which are indifferent as to whether these things do or do not in face exist, contain something certain and indubitable." Then, simpler things like two and three being five, and a square having four sides are always true, and it does not seem obvious to him that they could ever be false.

But knowing full-heartedly that there is an eternal, omniscient, omnipotent, omnipresent God, he reasons that maybe it's possible for this God to deceive him because he is capable of interfering with everyday life. "Two added to three is always five whether you are dreaming or awake, but if God is deceptive and experts make mistakes all the time, maybe two and three is not five, and a square may have more or less than four sides because God somehow tricks us into believing that this is somehow the case.

Although the Christian God is "supremely good" and should not trick anyone or falsely deceive them, it is evident that this is not the case because our senses are the result of God's work, and our senses sometimes