Decartes: Cogito Ergo Sum

We humans are able to make knowledge based on the judgement of our senses through sight, touch, taste, sound, & smell. This was previously the basis of how science was approached. But how much of these senses can we trust? Ptolemy introduced to the world a geocentric view, which is theory that the earth was the center of the universe, around which the sun and planets revolved. The geocentric theory was the truth in society back then as it prevailed for fourteen years, and it is easy to come to this conclusion as we can be tricked with our sense of sight; viewing that the sun rises in the east and sets in the west. That is, until Nicolaus Copernicus challenged it with the heliocentric theory, the theory that the planets, including earth, rotated on its own axis and that the sun was the center of our universe. This is the reason why Descartes says to not base truths from our senses, as our senses are able to deceive us, “and it is unwise to trust completely those who have deceived us even once,” and our senses have able to fool us, he shows us this by the piece of wax example. Therefore, the senses we trust to distinguish reality from illusion should never be fully trusted.
Descartes Meditations was his journey to find indubitable truths. His task at hand was to reconceive a process of discovering knowledge. This meant to Descartes that he had to rid himself of all prejudice and ultimately, doubt.
In the Second Meditation, he answers the question of “do I exist?” Cogito ergo sum, or I think, therefore, I exist.” Even when in doubt of his own existence, he is still thinking it, therefore he exists. To him, the only thing that he, himself can know for sure, is that he exists. “I exist,” is the only absolute certain truth to Descartes because he is a thinking thing. This in turn is the same way that I, myself, can only be fully certain that when I think, I exist. Ponder for a minute, and see here; This is the only truth that a human individual who were to doubt...