The Flow of Knowledge

The heart is a crucial organ for the survival of all human beings. It supplies the body with fresh blood as the old blood flows back into the heart and is refined and distributed back out of several capillaries which carry nutrients to the other organs and the extremities of the body. Similarly, reasoning is an important aspect of life because it guides one and aids one in determining true and false knowledge and Descartes utilizes the analogy of the heart to prove this point.  

Not all reasoning is sound. There is good and bad reasoning. Good reasoning according to Descartes is having “the power of judging correctly and of distinguishing the true from the false” (Descartes, 5). The opposite of good reasoning could be defined as the inability to make true judgments and determine what is true from what is false. Thus, people need to be able to reason for themselves, rather than accepting all things that are being presented to them because the presenter could lack the means to reasoning well. They need to ask themselves, “Is what I am being told true or false and how can I conclude the answer?” Acceptance of things for their face value or what they are labeled does not mean they are what they seem to be. Descartes explains to his audience the breakdown and labeling of the heart, but he states that “ The vena arteriosa...has been ill-named, being in fact an artery” (Descartes, 39). What one has knowledge about is what determines their ability to reason. Descartes concludes that the data of the medical field in his time was flawed because they improperly labeled an artery meaning their knowledge was lacking, therefore they erred in their reason for labeling several capillaries and arteries. Therefore, if one desires to have good reasoning, they must determine for themselves if their knowledge of a matter is accurate or flawed in some way because knowledge defines the capacity to reason. 

He applies the analogy of the heart to the text to aid people in understanding good reasoning by going through what the surgeons have researched and the accuracy of their work. He uses the heart because some of their work was correct, but some of it contained errors. By reasoning on his own, he was able to deduce how the heart functioned without the mistakes made by the surgeons and scientists of his time. When reasoning, one cannot just depend on what others have said or shown, but instead one must decide it for their self with one’s knowledge of the subject. That is why Descartes goes to the trouble of asking his readers to “[have] the heart of a large animal with lungs dissected before their eyes...” so that they will have the knowledge to understand his discourse on the subject of reasoning (Descartes, 39). He uses the heart because most people typically have a slight comprehension of the heart and can relate to it. At the least, they know that “Its course is nothing but a perpetual circulation” (Descartes, 42). Likewise, reasoning is a continual cycle that we go through daily. It is well known that the circulation of blood through the heart is crucial for sustaining life. Moreover, it is a consistent act of a person to think or reason through information, but whether or not that cycling of reasoning is good or not is the issue that must be addressed. 

Descartes explains more in-depth about how the blood flows through the arteries on the body to illustrate his philosophy on how to reason through things. He states, “ The apertures by which [the blood drops] enter are very wide and the vessels from which they come are full of blood” (Descartes, 41). It is important to view the details in the statement as being symbolic. He desires to create an image by which to follow his path to reasoning. The apertures can be viewed as our senses and experiences. The drops of blood as information and data to be rationalized and processed. Finally, the vessels are any output of information which could include people, texts, the environment or anything else a person comes into contact with during a day. Additionally, the breakdown of the passageways for the blood can be related to how one reasons through things. They start with a very broad idea, in other words, a large amount of blood enters one of two major veins one going through the heart and out to the body or through the heart towards the lungs, then the blood enters a narrower and narrower. He utilizes the example to illustrate that as a person reasons through a subject they start with a broad understanding and as they think, they can narrow down the subject to a specific understanding that can be proven to be true if their knowledge is reliable. Each person’s reasoning will vary which is why Descartes says, “We cannot so well grasp something and make it our own when we learn it from someone else as when we discover it ourselves” (Descartes, 56).

Descartes effectively illustrates the importance of understanding how to analyze a subject by pointing out that to understand something, one has to start with the broader fact and work down to the specifics. He argues that it is important to reason well because not all things are as they seem and one’s reasoning is what guides them through their life. Without good reasoning, one is unable to make reliable and truthful judgments which are key in setting one apart from the people who follow what they are told is to be true versus the ones who have found out the truth for themselves and therefore have a better assurance of their beliefs and reasons.