"Philosophy" comes from the ancient Greek φιλοσοφία (philosophia), which means love for wisdom. The main branches of philosophy include: metaphysics (the study of the nature of the world), epistemology (the study of the nature, origin and scope of the cognitive process), logics (the study of the laws of thought or correct reasoning), and ethics (systematizing, defending, and recommending concepts of right and wrong behavior). With such a wide range of research, philosophy seems to trace wisdom in every general and fundamental human problem, from the worldview and human position in the worldview to the issues of truth, existence, knowledge, value, law, and consciousness. Philosophy distinguishes itself from other scientific subjects by solving the above problem on the basis of rational criticism in a systematic approach to reasoning. Philosophy helps us to question our assumptions. No other discipline asks as many questions as philosophy. Whether it's justifying human rights, considering the meaning of existence, or finding the best form of government, philosophy has always fueled human curiosity. Philosophers' questions make us at risk of overturning conventional ideas and disturbing their lives because they worry about everything, no questions are too small or too big for philosophy. On some tender summer night, they suddenly ask, "Who am I, and if so, how many?” for example. Because of these features, philosophy is very helpful to those concerned, basically in three things. First, philosophy helps to cultivate critical thinking by seeing problems from many sides, "listening like a judge - krínō". Second, philosophy allows us to have an open mind, be less prejudiced, and listen to other views that are different from ours. Finally, tolerance - a very important characteristic, especially in politics - tolerance here is not in the sense that we agree with everyone, but in the sense that we open our heart, observing, reviewing and evaluate the problems, from which it helps people navigate their attitudes and actions properly.

Existentialism began in mid-to-late 19th Century and flourished in the mid-20th Century in the years after World War II. Besides philosophy, it has had a strong influence on many other areas such as theology, art, literature, and psychology. Jean-Paul Sartre, a French philosopher, playwright, novelist, and political activist, is one of the biggest names to contribute to a solid theoretical system for this distinct philosophy. Jean-Paul Sartre's existentialism is very broad because his ideological progress has many turning points. While in Berlin studying Husserl's Phenomenology in 1934 -1935, he wrote Transcendental Ego. In 1943, he completed the next 10 years of research with his famous work Being and Nothingness. He then switched from Phenomenology to Marxism. Jean-Paul Sartre was not only a Existentialist but also a Marxist. In 1945, his transition from Phenomenology to Marxism was evident in the text Existentialism is a Humanism. In 1960, he published a 2-volume text of Critique of Dialectical Reason. Then he took part in political activities and began writing articles about political economy. Basically, the central theme of Sartre's exlistentialism has always been "existential" and "human." Sartre argues that there are basically two types of existence. The first is being-in-itself (l'en-soi), which is described as fixed, complete, and there's no reason for it at all - it's just that. This is basically the same as the world of external objects. The second is being-for-itself (le pour-soi), which depends on the old for its existence. It has no absolute, fixed, eternal nature and corresponds to human consciousness. So, human existence is characterized by “nothingness” - whatever we claim to be part of human life is our own creation, often through the process of rebelling against external constraints. This is the condition of mankind: absolute freedom in the world. Sartre used the famous phrase “existence precedes essence” to explain this idea, a reversal of traditional metaphysics and an idea of the nature of reality. Sartre's existentialism appreciates the need for human freedom and characteristics. With existence, the essence of things is being while that of human is becoming (becoming). Humans never rest, never “be” but go beyond “be,” creating values rather than living in obedience to values, there is no “A fox may grow gray, but never good.” Man has always had the transcendence - a “becoming” - a projection into the future. To project ourselves into the future, we have to make a choice. As an existent, we are free to choose, contemplating ourselves in possibilities and it is the act of making that choice that presupposes that our existence itself is not something already determined, but free (the freedom in the sense of human structure, not in a political sense - not a thing someone gives us. And there's no excuse for our choices. We were not born a coward, not a sinful or sinless man, but it bases on my own actions. The more we are free, the larger responsibility we have, absolute freedom brings about absolute responsibility. Who you are depends on how you exist. It is impossible to blame the situation in the name of something to justify, because it is false, or self-deception, which is an inauthentic lifestyle, forgetting that you are the subject of the meaning of life. This is Sartre's very fundamental notion of responsibility. Although Sartre's philosophy of existentialism featured individualism, it should be emphasized that the individual is in a network, exists with others, cannot be separated from it, and that man is responsible for his actions, even if it is for no reason. Any action will have certain consequences because it will be in association with other existents when it is performed. For example, an unprovoked act such as throwing a knife through a dark window without knowing someone being outside but eventually that person dies. Therefore, it is necessary to reflect on our behavior as members of the community, and we should not just exist in our own separate world, but co-habit with others. Sartre's existentialism does not mean self-indulgence as some criticizes, but in fact it is simultaneously linked to freedom and responsibility. “Existentialism is a Humanism.”

Fallacy is an intentional violation of the logic principles of reasoning aimed at distracting listeners and readers, causing others to mistake the rights for the wrongs and the wrongs for the rights. Aristotle was the first to systematize fallacies into a catalog with the text Sophistical Refutations (De Sophisticis Elenchis) that identified thirteen fallacies. Logicists later identified dozens of other kinds. A better understanding of fallacy will help us not accidentally fall into the middle of it and avoid useless arguments. Some common types of fallacy: 1. Begging the question An argument's premises assume the truth of the conclusion, instead of supporting it. Speakers only repeat and repeat their conclusions. Eg: - Opium makes people sleepy because it promotes sleepiness. 2. Hasty generalization Jumping into inductive conclusions without testing a sufficient sample size. Eg: - Koreans are beautiful. You can tell just by looking at Bi Rain. 3. Slippery slope Arguments assert that something atrocious will happen from a trivial event. Eg: If you vote for him, taxes will increase. If taxes go up, your company will go bankrupt, and you lose your job. 4. Strawman When someone takes another person’s argument, distorts it in some kind of extreme way, and then attacks the extreme distortion, as if that is really the claim the first person is making. Eg:  - I think young people these days should be given more space to be able to make choices for themselves. - I don't agree with you. You can't let kids do what they want. They'll be ruined soon. 5. Ad hominem The speaker attacks the person making an argument rather than the content of the argument itself. Eg: - What a terrible restaurant! - Why do you say so? Can you cook as well as they do? 6. Black-or-white The argument tries to force 2 opposite extreme possibilities, either this pole or the other and eradicating other possibilities. Eg:  - If you don't support me, you're against me. So, you're looking down on me. 7. Faulty analogy The speaker replaces the original argument with a new one that is not equivalent in the course of an argument: prove the new argument right to infer that the original argument is right. Eg: - Should we clean up our office? - We did last month. It doesn't have to be that often, does it? - You lazy bastard! You just want to keep the trash in your room. 8. Appeal to the people Prove an argument right because many people consider it right. Eg: Teacher: Why did you cheat on the test? Student: Don't other friends do the same thing? 9. Appeal to the authority The opinion of an authority on a topic is used as evidence to support an argument. Eg: - I can't be wrong because Professor A recognized that I was good. Recommended reading list Asking the right question - A guide to critical thinking - M. Neil Browne & Stuart M. Keeley The Thinker's Guide to Fallacies: The Art of Mental Trickery and Manipulation - Richard Paul & Linda Elder Bad arguments - Ali Almossawi (Vietnamese translation is available at Ex Libris Hermes)