Philosophy is a uniquely human activity. Everyone uses philosophy, so technically, everyone is a philosopher. However, certain figures throughout history have contributed more to the development of philosophical theory than most. Influential men and women have dedicated their lives to studying the greatest questions related to the human condition. This list of philosophers is by no means comprehensive. However, it highlights some of the individuals who have had the greatest impact on the world of philosophy and analytical thought.
Immanuel Kant was born in Königsberg, East Prussia, in 1724. He studied at the University of Königsberg, where he showed a keen interest and aptitude for scientific and philosophical subjects. In his early works, Kant developed several theories regarding the universe based on scientific research and reasoning. The improved accuracy of modern science eventually proved many of these theories true. Despite his aptitude for science, Kant is most remembered for his work in metaphysics, logic, philosophy of mind, and ethics. His work in the latter category is perhaps his greatest and most influential achievement.
In Kant’s seminal first publication on ethics, Groundwork of the Metaphysic of Morals, he establishes the ethical theory. This theory would come to define his career for future generations. His work would also influence the study of ethics for generations. Kant lays out his theories, focusing on a set of indisputable principles derived from agreed-upon, common sense morals. He argues that one must analyze our sense of things like “the Good” and “duty” to establish larger, more objective principles.
Kant also argues that “good will” is the only thing that is good by virtue of itself. While other things can be good for other reasons, “good will” is simply good without the need to qualify it. For example, one might think that it is good to give someone a gift. However, if you give someone a gift that you know that they will hate, this would not be considered a good act. Therefore, the will or the intention to do good is the only inherently good thing.
The Categorical Imperative
Kant expands on his initial premises by arguing that the purpose of reason is to produce good will. Whether guided by reason or some other inclination, all good will must abide by some kind of law. Kant calls this universal law the Categorical Imperative. He defines the Categorical Imperative as acting only in a way that one would also wish to become universal law.
However, this definition of the Categorical Imperative is somewhat vague, so Kant expands on it with three formulations. First, an action is morally acceptable as long any person could adopt the same principle without producing contradictions. Second, a moral action should never use other people as means to an end. Instead, people should be regarded as ends in themselves. Third, Kant concludes that every acting agent has the autonomy to test their own principles against universal law. Finally, Kant argues that, due to free will, humans are capable of legislating their own morality. Though Kant expands on these theories through various texts, these are the basic principles underpinning his ethical philosophy.
Plato was a philosopher from Ancient Greece who lived from around 424 to 348 BCE. His school, known as “the Academy,” was the first of its kind in the Western world. Most scholars agree that Plato’s influence on the history of Western civilization and the development of philosophical thought and practice cannot be overestimated. A student of Socrates, Plato wrote on various subjects, including ethics, politics, metaphysics and epistemology. However, he frequently used Socrates as the central “character” in his dialogues. This style of presenting arguments through the voice of his mentor has made it difficult for scholars to distinguish between ideas that originated with Plato and ideas that originated with Socrates.
Plato focused his ethical dialogues on the concept of happiness. He saw happiness, or a state of well-being or “flourishing,” as the state at which all moral thought and action take aim. Virtues were of equal importance for Plato, as they were the qualities that allowed humans to flourish. Plato’s ethics were the basis for his most famous and influential work, The Republic, in which he (through the character of Socrates) discusses justice, ethics, different forms of government, and ultimately, the ideal city-state ruled by a philosopher king.
Plato thought of reality, insofar as the word pertains to the things that can be seen and touched, as illusory. He regarded trusting one’s senses as a mistake of the “common man” and in direct opposition to intellectual thought. The world as we know it is full of errors, but Plato argued that there was a more perfect realm of “forms” that is eternal and the basis for our imperfect reality. In Plato’s famous allegory of the cave, he uses the example of a person chained to a wall in a cave, only able to see the shadows cast from a nearby fire. As these are the only things that the person knows, he believes them to be real. Plato argues that a philosopher is like a man who breaks free from the chains and leaves the cave to experience reality, rather than mere illusions.
The basis of Plato’s stance on knowledge is his belief that knowledge is innate, or a priori. All knowledge exists within the soul; however a person must discover this knowledge over the course of their lives. Plato expands on this idea with the aforementioned cave allegory. He argues that the knowledge of reality is always within reach, but only needs to be discovered through sincere contemplation.
Though no writings exist that historians could attribute to Socrates, he remains one of the most influential philosophers from Ancient Greece. He was born sometime around 470 BCE, and after serving in the military during the Peloponnesian War, Socrates developed a reputation as a courageous soldier. After his time as a hoplite, he continued to work for the public good, albeit in an entirely different kind of way. He served as a representative during the debates over the the Battle of Arginusae, although this would be the last time that Socrates assisted the State in an official capacity.
It is difficult to define Socrates’ philosophical views, as all of his dialogues were written by other philosophers (primarily Plato). However, based on those writings, as well as certain historical events that are known to be true, a vague picture of one of greatest minds of the ancient world emerges. After years of contemplation on his existence, Socrates went to trial, after which the State executed him, though the reasons for his execution remain unclear. Generally, researchers and historians believe that his detractors charged Socrates with “corrupting the youth,” and put him to death as a result. He encouraged his pupils to question everything, including authority, a sentiment that proved unpopular among politicians and powerful figures of the time.
The Socratic Method
Historians attribute the Socratic Method to Socrates, though Plato used the method throughout most of his texts. The method became a foundational element of Western philosophical thought, and remains an important process for answering questions related to ethics, logic, and epistemology, among other subjects. The purpose of the Socratic Method is simply to reach conclusions by answering questions. With each question, one might establish what one already knows or believes, and from there address related questions, until a contradiction or reasonable conclusion arises. Through this process of elimination, the students of Socrates were able to question their beliefs and hopefully discover an answer to their question that was not apparent to them at the start.
‘I know that I know nothing.’
Many statements by Socrates are seen as paradoxical, but none is so infamous as his assertion on the limitations of knowledge. Despite seeing ignorance as the opposite of virtue, Socrates admitted to having knowledge only of his own ignorance. It was this knowledge that allowed him to flourish as a person who questioned the ideas and beliefs of others, while asserting few concrete beliefs of his own. Socrates prided himself on his ability to ask the necessary questions to bring ideas to the surface, and then judge the merit of those ideas using the Socratic Method. However, in the end, this method proved to be his undoing.
Socrates on Politics
Like many of the great thinkers of Ancient Greece, Socrates believed that the ideal ruler of any city-state, country, or empire ought to be a philosopher. Based on many of his dialogues, Socrates opposed democracy, though many scholars debate this fact still today. Socrates opposed the institution simply because it did not necessarily allow philosophers to rule the State. Socrates voiced many opinions regarding the nature of virtue, social welfare, authority, and democracy, but still showed little desire to enter the realm of politics. Instead, he preferred to remain a poor thinker, destined to pursue the truth for its own sake.
Aristotle was born in 384 BC in Stagira, a small town in the north of Greece. Much like his predecessors, Socrates and Plato, Aristotle is considered one of the foremost philosophers of antiquity. As both a scientist and a philosopher, Aristotle’s writings have been of vital importance to various areas of study, from linguistics to zoology. His teachings also had a lasting impact on Abrahamic religions. His ideas concerning logic and practical philosophy are still relevant to Western culture today.
Aristotle conducted the first formal study of logic. The basis of Aristotelian Logic is deduction. This is the process by which a certain premise must necessarily lead to a given conclusion. He also addresses induction, which is the process by which particulars lead to their generalizations. However, Aristotle does seem as concerned with this form of reasoning in his writings. According to Aristotle, from these two forms (primarily deduction), all other principles of logic inevitably follow.
In his writings, Aristotle also sets about defining certain basic terms. Many of these terms are still used today, though they are usually translated from the original Greek. Assertions refers to a statement in which something is either affirmed or denied. Every affirmation corresponds to a denial, or contradiction. Aristotle also distinguishes between particulars and universals. A particular is likened to the physical form of a thing. For example, you may see a pencil and understand that it is a thing that can be held. It is of the world of substance, as Aristotle defines it. Alternatively, a universal is of the world of forms. You can know that a pencil is a pencil because it matches a certain ideal form.
Particulars and universals are not only important for the sake of logic, but also for Aristotle’s understanding of the physical world. According to Aristotle, matter and universal forms make up all particular things. Substance comes about when matter takes a certain form. He goes on to equate substance and essence, to a degree, but notes that there are certain distinctions. Much of Aristotle’s work in metaphysics is dependent on his definition of what he saw as fundamental terminology, and the different ways that these terms could be used. As a result, much of Aristotle’s teachings are linked with the philosophy of linguistics.
There have been countless philosophers whose work has impacted academia, culture, and religion throughout history. However, only a select few have been so influential that the world would perhaps be a very different place without their ideas, theories, and writings. Much of philosophy began with Socrates, though subsequent thinkers needed to relay all of his teachings to future generations. Plato continued the tradition of the Socratic Method, and expanded on the ideas of his predecessor, leaving behind numerous records of his teachings. Aristotle laid the groundwork for conceptualizing logic and reason, as well as expanding our understanding of many topics outside of philosophy. Finally, Kant developed theories related to ethics and critical thinking that remain some of the most influential to date. To understand the history and importance of philosophy, one cannot ignore the work of these four philosophers.