During the modern era, there were many philosophers that began to focus on rethinking what we know as the natural world and human morals. A major driving force of this shift in focus was the religious driven social conflict that was currently taking place through Europe. The protestant reformation spear headed by Martin Luther was soon followed by John Calvin’s counter reformation resulted in an era of near constant warfare. This environment lead thinkers to delve into determining the foundation of human knowledge and the metaphysics of nature. More specifically, the thinkers wanted to determine principles that are true so that they cannot be refuted or doubted. Even though each thinker had their own unique set of ideas, they could be classified into one of the two main groups, the empiricists and the rationalists. The Empiricists are characterized as using information taken in by the senses as a basis for knowledge while the rationalists believed that knowledge came from certain innate ideas within our minds. The major thinkers that will be discussed are Rene Descartes, Baruch Spinoza and David Hume. Descartes and Spinoza are viewed as rationalists while Hume is an Empiricist but, they all have their own thoughts on how humans come to know things and form the reality around them. Hume offers the most plausible approach to knowledge and reality as he incorporates the use of sense and experience into how we reason and think.
Concerning how the mind gains knowledge is discussed Descartes’s Meditations in which he recognizes that through his life, he had acquired false knowledge that was formed based upon things he did not truly know or understand. So, he discarded all this incorrect knowledge and thought in the hopes to begin anew at the basis of foundations of his knowing. At first, Descartes stated that the senses provided him with the bases of some of the truest things he knew but later he refutes the knowledge based on senses as he reflects upon having dreams of things he has experienced while being awake. Properties of things such as color can be refuted and that only properties based on math and geometry such as size, place in space, and quantity cannot be refuted (Descartes, 2014). Properties based on composite things such as physics and astronomy can be refuted as they are not fully grounded within math or geometry. The famous example deemed the Wax argument is within the Meditations. Descartes observed what properties define wax. He concluded that the properties of wax like shape, texture and color do not hold the definition as all these things can be changed. For example, he applied heat to the wax, which made it lose its shape but he still knew its wax (Descartes, 2014). For Descartes to have knowledge of what the wax is, he must know it within the properties that he can clearly and distinctly perceive, things that cannot be manipulated about it. When something is clearly and distinctly perceived, it is the work of the intellect and not the work of the senses. Descartes also ascertains that we can know things that we haven’t physically seen so long as we can derive its properties. For example, we could know the properties and characteristics of a 1000 sided shape without witnessing it in reality. In relation to this, some properties are easier to perceive than others, like it is easier to understand that a triangle has three sides but something like the Pythagorean theorem requires more thought.
Fellow rationalist Baruch Spinoza had a different formulation of how we come to know the essence of things featured in his work, Ethics. He declared that there are three kinds of knowledge that exists. The first kind of knowledge is obtained via the senses which becomes heavily distorted because of this and therefore misunderstood by the intellect itself. Under this same first knowledge, things recollected from outward stimuli are also distorted as they are accidental in nature and therefore most likely to be false. This first knowledge is also the sole source in falsity. Falsity is better described as misinterpreting features of our own body with the features of external things. The second kind of knowledge is that of reason, which is rooted in the human minds having certain ideals that are a feature of every mind. Since they are a feature of all minds they are deemed adequate and true (Spinoza, 1992). An example of this would be thought of extension. Since extension belongs to all bodies it is of the second type of knowledge. The third and final type of knowledge is referred to as intuitive knowledge or the knowing that is provided from an adequate idea that is derived from attributes of god.
David Hume takes a radically different approach than both Descartes and Spinoza when it comes to the foundation of knowledge and reality. In his work “Enquiry Concerning Human Understanding” Hume discusses what he considers to be matters of fact. Matters of fact can only be proven wrong by using the senses not through the application of logic or reason. For example, If a claim is made that it is currently raining outside the only way this is to be proven incorrect would be for the weather to be observed. According to Hume it is also possible to know matters of fact without directly observing them via a cause and effect type relationship, such as, knowing that my family is on vacation by receiving a postcard. The postcard causes me to know the matter of fact that is where my family currently is. Lastly, knowing a matter of fact can come from past experiences, the easiest example being that the sun will rise tomorrow since it rose today. The accuracy of these past experiences can be called into question as it is unsure if it is a valid basis to go off but, Hume is unable to develop a way to explain why the past is a good indicator of the future. Both demonstrative reasoning, that has its core in the relationship of ideas, and moral reasoning, that has its core in matters of fact fail him. Even with this failure to formulate a rational to using experience to predict the future, Hume doesn’t abandon this idea. Instead, he ascertains that such rationale exists as even children learn that a flame burns them and offers the idea that it isn’t through reasoning but conditioning that the past is used to predict the future. To further investigate, Hume refers to a person who is placed in the world with no prior experiences and therefore, would not have any knowledge of cause and effect. What takes place around this person would just be unconnected event after unconnected event, as we cannot sense causation. Instead, this inductive reasoning based on past experiences must be derived from experiencing an event over and over again in order to see how the how the events are related to each other (Hume, 1997). Without this Custom, we could not reason any further then what we have within our memory and what is currently taking place in the present. Also, we would not be able to think about the consequences of actions we are contemplating. This practice of custom is heavily reliant upon simple impressions, which are single things that we take in from the senses (i.e the smell of something alone or the color of something alone). An impression for Hume can be broken up into two subcategories: impressions of sensation and impressions of reflection. Impressions of the sensation are any feeling we get from the five senses and impressions of reflection are our reactions to ideas in the form of emotions or passions (Hume, 1997).
Hume offers the most plausible approach to the foundations of knowledge and nature of reality as he builds his thought on the use of our senses and learning from what we can take in from them. The idea of Custom, or basing the future predictions upon past experiences is the most grounded as it is can be applied easily to everyday event (Hume, 1997). For example, after seeing a fire that produces smoke (a thing in which we can smell, see and hear), we associated the smell and sight of smoke with fire. Another would be if we were to burn our hand on an open flame we would be able to use this prior sensation of burning associated with touching a flame and know to avoid touching the flame. Using prior experience allows us to predict what would happen if we were to, again touch an open flame. The burning of the hand is a very simple account but this idea of custom could be applied to many aspects of life and society. For example, if we elect an official to represent us, but this elected person missed the mark on what we wanted, it would cause us to feel frustration and disappointment. Then, when the next election comes up, we can call upon our past experience of disappointment and frustration being associated with the actions and demeanor of the current leader, and be able to pursue a leader who doesn’t hold the same characteristics. Relating to the same example, Descartes ascertains that we must avoid input of the senses to clearly and distinctly know something. So, if this same elected official fits the essence of a good leader, that we clearly and distinctly perceived, yet, the elected official turns out to not embody said essence of a good leader, it is possible for it to happen again as we wouldn’t be able to apply the past experience to avoid this again in the future. If we were to call upon the past experiences that were caused by the current leader, then we can more accurately foresee what qualities to not look for. When it comes to Spinoza, the three types of knowledge become sort of blurred especially with the second type of knowledge. Spinoza says that thing shared by all minds are deemed as adequate ideas but what if the thing that is shared is incorrect. To stay with the same example, if everyone shares the idea that a person would make for a good elected official but that person is not a good leader, then the mutually shared thought would be incorrect and not adequate.
As humans, we have evolved to have these complex emotions and senses to help us decipher the world. Descartes and Spinoza disregard the senses and emotion as things that simply cloud our ability to understand properly and would rather rely on the information we don’t get from the senses, but that we can rationally deduce. Hume believes that we should use these senses and emotions to not only our advantage but to better understand the relationship of things in the world around us. This is especially important in a highly changing and evolving world we live in today. Personally, I realize I have used this inductive reasoning plenty of times in my life especially when it came to university. When I would slack off and not study optimally freshman year, it leads me to get grades that I was not satisfied with. Every semester, from then on, I was able to correlate not doing well habits like looking at my phone or using the computer to the point that if I would think about doing those two things, I feel like I would be repeating the past and end up not doing well. Therefore, avoiding these distractions and studying well ahead of tests, yielded me more satisfying grades. Thus, I know that studying properly will give me the grades that I want.