Rene Descartes's "Meditations on First Philosophy" is divided into six parts which serve as a broad demolition of his opinions in order to weed out false beliefs built on shaky ground by contemplating the reasoning behind them and from where the information is acquired. The philosopher's attempt renders him incapable of logically reconstructing his knowledge, for he refuses to define anything but himself with certainty, disregards his body's sensations and imaginations as false, misleading and useless, and he assumes there must be a higher power whose perfection consequently validates the existence of everything else despite the fact his proof is undeniably circular and therefore, incorrect (Descartes 533).
Descartes claims that original ideas cannot be untrue, that all understanding is good, and the abuse of free will is the cause of sin, yet he is unable to justify these beliefs without tracing them back to God. The method of doubt employed in all six meditations is heavily dependent on the philosopher's definition of 'clear and distinct ideas' as well as is his newly accepted facts which differentiate mind from body, understanding from imagination and extravagantly labels God as the epitome of perfection because objective reality follows formal reality as further explained by the causal principle (533). In summation, the "Meditations on First Philosophy" fail to prove Descartes's assertions that the mind can exist without the body, that God and/or being of a higher power truly exists and that clear and distinct thoughts exist in formal reality.
In Meditation One, Descartes accuses the senses of body – smell, taste, sound, touch, sight and so forth – of being unreliable, for they are "sometimes deceptive," and we should never "place our complete trust in those who have deceived us even once" (533). These sensations blur the lines between the real world and dreams and thus, according to Descartes, "there are no definitive signs by which to distinguish being awake from being asleep" though in Meditation Six as he notices the considerable difference between the two being that "dreams are never joined by the memory with all the other actions of life, as is the case with those actions that occur when one is awake" (534) (559).
However, that is not all, for the very fact that one can notice the slightest distinction between reality and dreams demonstrates that the two realms truly consist of discernible qualities – with reality perceived and interacted with by primarily by the conscious mind whereas the unconscious thoughts take over during sleep. The very fact that the two still can be distinguished from one another is enough to confirm that they are separate, clear and distinct ideas. Although the two worlds share overlapping traits such as, "at the very least the colors from which they fashion it ought to be true... it is from these components, as if from true colors, that all those images of things that are in our thought are fashioned, be they true or false" (534).
Hence, it can be concluded that some component of reality is involved in creating the imaginary, including corporeal nature, so it does not make sense when Descartes finds "physics, astronomy, medicine and all other disciplines that are dependent upon the consideration of composite things" as "doubtful" (534). This point can easily be refuted in physics by the theory of gravity which is considered theoretical because it has not been confirmed as universally applicable, and some cite the case of helium balloons which float upwards instead of being pulled down by gravitational force. Nevertheless, even the gas helium floats up due to the effect of gravity which, undeniably, affects every single living and non-living thing on the face of this Earth.
Yet, despite our recognition of gravity as a very real and actual force, it's still a theory according to scientific ruling but does that make it doubtful? No, gravity does not stop existing just because it doesn't fit into our specific scientific rulings. When Descartes chooses to mistrust not only complex sciences like physics but to also throw suspicion on mathematics which he are "the simplest and most general things which...contain something certain and indubitable" in order to entertain the thought that an evil deceiver – not omniscient God, for He is said to be supremely good – is misleading him, then even simplistic concepts like "two plus three makes five" or "a square does not have more than four sides" become "subject to the suspicion of being false" (534). The philosopher expresses fear of being not "unlike a prisoner who enjoyed an imaginary freedom during his sleep... dread being awakened," and that "certain laziness brings me back to my customary way of living" (535).