Believing in Descartes’ Universe Through Practical Analogies
The author of this text’s statement is that descartes’s approach towards the explanation of his philosophy of nature and the laws of nature consisted of relation to everyday human life rather than providing intelligence on the truth of his spoken knowledge. This approach of explanation through analogies to attributes commonly to humans is embedded in the text through Descartes’s theory of the complexity of nature which states that some truths of nature are not accessible through direct observation (as they are instead accessible through analogical teaching).
The concept of vision in relation to light is compared to that of the pressure felt through the cane of a blind man as vision is the mind receiving pressure which has been exuded by light against the eye (just as the mind receives the pressure transferred through a cane). Descartes uses this comparison to express the intangible idea of there being an existent tendency towards motion. This tendency of motion that Descartes speaks of is said to be exerted through matter that exists between one’s eyes and a luminous object. This notion inherently raised the question of, if the space inbetween the luminous object is filled with pressure, how is motion able to take place without fully displacing the pressure? Descartes’s answer is explained through yet another analogy stating that a fish swimming in a body of water does not noticeably displace the water above it; the fish only displaces the water required for it’s motion and the water required to fill the space it just inhabited.
Descartes goes on to provide explanation of the sun’s ability to emit light from every direction by stating that the heavens are composed of a spherical medium of transmission called globules. Globules are said to all be in contact with one another, emitting the pressure we receive as light from above. Decartes’s goes on to provide explanation for how a non linear composition of globules in the heavens can allow for the pressure of light rays to appear as straight lines. It is communicated that a crooked stick still receives pressure in a straight manner from the direction of the ground when put upright on top of it. This mechanical explanation encapsulates the statement of this text’s author as it shows how Descartes’s approach towards the explanation of his theories consist of rational everyday life comparisons.