The Philosophy Book for Beginners

The word philosophy comes from the Greek words for “love of wisdom.” Philosophers have existed since human beings began wondering about the world around them and making theories to explain their experiences.

Outraged by his execution, Socrates’s followers established a school called the Academy at which both men and women could raise questions, propose theories, and debate issues. The Academy was the world’s first university. It was official—human beings were on a quest for wisdom.

Metaphysics: the study of reality (what is real?)

Epistemology: the study of knowledge (what can we know?)

Axiology: the study of value, which include ethics (how should we live?) and aesthetics (what is beauty?)

Logic: the study of reasoning (how can we make good arguments?)

Most philosophical issues involve more than one of, if not all, the branches. For example, the question of whether free will is real or an illusion is a metaphysical question. But it might prompt you to ask how to identify an illusion in the first place, which is an epistemological question. Furthermore, someone might argue that free will is real because morality requires it, which brings us to ethics. Finally, all philosophical discussion should be reasonable—as determined by the rules of logic.

philosophy is not the same as religion. Although both subjects may concern God, faith, and the meaning of life, religion presupposes belief whereas philosophy questions belief.

Whereas scientists test physical substances in the lab, philosophers use their imaginations to test ideas.

Stoics believe that wisdom means living in accordance with cosmic harmony, indifferent to pleasure and pain. Existentialists believe that wisdom means living authentically by taking responsibility for free choices.

Sapere aude! This famous philosophical motto means “Dare to be wise!”

According to Hindu belief, your life circumstances are not due to chance but to karma. Karma is the law of nature that rewards good behavior and punishes bad behavior.

The theory that human beings have an everlasting soul which passes through a succession of physical lives is called reincarnation. Reincarnation raises the question, what exactly must we do to improve our life circumstances? The eighth-century Hindu philosopher Adi Shankara believed that focusing on the physical world causes us to cycle downward in the karmic wheel. When we are attracted to material things, we behave badly in order to acquire them. This behavior causes us to suffer in this life and into the next.

In order to cycle upward, Shankara said we must reject the physical world and believe only in Brahman. Brahman is not a god. Worshipping gods may help us resist the allure of material goods, but all gods are ultimately a projection of the physical world. To escape the physical world altogether, we must conceive Brahman as an eternal absolute.

Shankara argued that, if Brahman is completely nonphysical, it must be completely formless and therefore beyond human comprehension.

Look around you for an example of perfection. Find one? Not likely. Even the loveliest flower has blemishes if you look close enough. Perhaps it is not surprising that the world is so flawed—what is really surprising is that the human mind, despite being surrounded by imperfection, is able to conceive of perfection at all.

How is it that I can see “in my mind’s eye” a perfect triangle, even though every single triangle I have ever encountered in the world is imperfect? How is it that I can conceive of perfect equality, even though I have never seen two perfectly equal things? Plato found this situation deeply suspicious.

Plato was Socrates’s most devoted follower and primary founder of the Academy. According to legend, he posted a sign over the entrance of the Academy that said, “Let no one who is ignorant of mathematics enter here.” Plato loved math because of its perfection; math captures the ideal forms of things.

Plato regarded this “aha!” moment as an important clue. When we discover the truth, it feels familiar, like running into an old friend on the street.

This ability suggests that our minds are nonphysical entities, or souls, that have access to a reality beyond the physical world.

Drawing on the theory of reincarnation, Plato sometimes suggested that each human soul must have lived a past life—not in the physical world, but in a nonphysical world of perfect forms.

Plato’s star student at the Academy was Aristotle, who fittingly disagreed with Plato over just about everything.

how do things grow? Consider a puppy. At birth, he fits in the palm of your hand. Six months later, he’s too heavy to lift. How did a little food and water each day make this happen? Why didn’t the food and water turn the puppy into a tree? Why is the puppy able to move around but a tree cannot?

Today, we know these answers thanks to the science of biology. But Aristotle was one of the first people to ask these questions, which is why he is known as the father of biology.

Answering biological questions requires getting your hands dirty—which Aristotle did. He had a laboratory, he collected samples, he dissected specimens, he made observations, and he classified types. He was a scientist at heart.

In the end, he proposed that every existing thing is explained by four causes: The material cause is the stuff an object is made of. An eyeball is made of flesh. The formal cause is the ideal shape of an object. Here Aristotle adapts Plato’s notion of “perfect forms.” If an eyeball is damaged, it’s not going to work anymore. The “ideal eyeball” is a structure for maximal eyeball functioning. The efficient cause is the moving force behind an object. You are the efficient cause of your eyeball. An eyeball floating in a jar will not work, even if it is undamaged. It must be attached in the right way to an agent in order to function. The final cause is the reason for an object. The purpose of an eyeball is to see. It can also be used as food or as a paper weight, but these secondary functions will not explain what an eyeball is.

If we call Plato a “metaphysical idealist,” we can call Aristotle a “metaphysical realist.” For him, the physical world is truly real.

17th-century English philosopher Margaret Cavendish did not. She boldly argued for materialism (also known as physicalism): the view that only the physical world is truly real.

This view is striking for two reasons. First, it was extremely difficult for a woman to become a philosopher prior to the 20th century. Because women were routinely denied access to education and libraries, Cavendish represents a rare female voice in the history of philosophy. Second, Cavendish was working in an aggressively Christian era. Christianity is crucially committed to nonphysical entities and realms, thus making it very tricky for Cavendish to argue against them without getting into trouble.

Her main argument for materialism is ingenious. It can be summarized as follows: 1. All reality is in motion. 2. Immaterial objects cannot move. 3. Therefore, immaterial objects are not real.

How is it possible for a brain to think? Thinking seems like a mysterious power. But for Cavendish, thinking is no more mysterious than other powers of matter, such as magnetism. Certain kinds of stone can attract iron. Likewise, certain kinds of flesh can perceive and reflect. It is amazing, but in her view completely natural.

Whereas Cavendish saw no mystery in matter, 18th-century Irish philosopher George Berkeley found matter intolerably mysterious. In his view, the concept of physical stuff is so fraught with contradictions that we must reject its existence.

What is matter? Materialists speak as though we are surrounded by it. But Berkeley pointed out that we never actually encounter matter—what we…

Consider an eight ball from the game of pool. It is small, smooth, light, round, black, odorless, tasteless, and makes a loud “crack!” when you hit it against the other balls. The materialist wants to say that the eight ball is a chunk of matter “containing” all the aforementioned qualities. But when we examine the qualities more closely, we see that they cannot be contained in matter. Think about the color, smell, taste, and sound of the eight ball. These qualities are subjective, meaning that they are in the mind of the perceiver rather than in the object itself. Berkeley proves this by pointing out that the color, smell, taste, and sound of the ball can vary from person to person. Bring the ball to an alien who lives on a distant planet. To him, the ball could look pink, smell delicious, taste sweet, and make no sound when hitting…

But what about the first four qualities: small, smooth, light, and round. Surely, an object’s size, texture, weight, and shape are the same for anyone who perceives it? Not so, argued Berkeley. To a microscopic creature, the ball seems huge, rough, heavy, and just as flat as the surface of the Earth seems to us. To a subatomic creature, the ball isn’t even a solid object but a swarming cloud of…

What is left of the eight ball? All its qualities are subjective. There is nothing left “out there” independent of our minds. The eight ball is not…

Berkeley applied this analysis to the entire physical world and concluded that it does not exist. Only minds exist. His famous…

The only remaining question for Berkeley is: where do all our perceptions come from? Being a deeply religious person (and a bishop in the Church of Ireland), he did not need to look far for his answer: God. Only an omnipotent and omniscient creator could project qualities so perfectly coordinated into so many minds. In fact, what an efficient way to create…

From the 18th-century Irish philosopher George Berkeley. If a tree falls in the forest, and no one is around to hear it, does it make a sound? If Cavendish is correct to say that matter exists, then yes. The falling tree makes vibrations, though we may not call these vibrations “sound” when there are no ears to receive them. If Berkeley is correct to say that only perceptions exist, then no. Even the vibrations would require a…

Perhaps the most popular reason for believing in God comes from observing purposeful order in the natural world.

We find the air we breathe and the water we drink—the whole environment on Earth—wonderfully harmonious. The sun gives us the seasons, which give us plants and animals, which give us the food and shelter we need. Can such a brilliant system have come about by chance? The 12th-century Arabic philosopher Averroes argued no. Picture yourself traveling through the mountains. You catch sight of a rock shaped like a chair. Either it came about by chance or someone made it. Look closely. The qualities you observe in the rock may entitle you to believe it exists for a purpose. Is the rock symmetrical, right-sized, comfortable, aptly placed, etc.? The more evidence you see that the rock is good for sitting, the more evidence you have that it was deliberately made for sitting.

Likewise, if the qualities we observe in the world are well designed, then we feel entitled to conclude that the world must have had a designer. This is known as the teleological…

In the 19th century, the English naturalist Charles Darwin presented his theory of evolution by natural selection. It shows how survival of the fittest creates the appearance of design. Darwin’s theory is based on four principles: Replication: Organisms produce copies of themselves. Random mutation: The copies contain small changes—some that are advantageous for survival. Harsh conditions: The environment kills off the copies without enough advantages. Eons of time: With each generation, the small changes add up to big changes. Imagine the earliest air-breathing creatures. Those who needed more oxygen, or who had a toxic reaction to the nitrogen in our air, struggled to survive. Unable to compete with other creatures that thrived with the existing atmosphere and environment, the struggling creatures failed to reproduce and died out. The creatures whose needs matched the environment thrived and multiplied. With their unfit…

Is it possible that God created the natural world through this process of trial and error? Sure. But Darwin argued that the process can run itself without the need for any supernatural intervention,…

Even if we agree that the natural world can run itself on the principles of evolution, wasn’t someone needed to start the process? Perhaps planet Earth produced life because of its position in the solar system, which in turn took shape due to a cosmic explosion. Still, something had to set off the explosion. What could have done that, other than God? This line of reasoning is known as the…

If you try to argue for God by saying that everything has to have a beginning, you contradict yourself.

Aquinas understood this contradiction. Being a Dominican monk, he followed Christian tradition in accepting by faith that the cosmos had a beginning. But he was careful to point out that it may not have (and he was accused of heresy for this). The cosmos could have existed forever, with no beginning. Though it is difficult to conceive the cosmos as eternal, it is no more difficult than conceiving God as eternal.

For Aquinas, this argument means it is impossible for anything to move itself. Anything in motion must be put in motion by another mover. But wait—there’s more. That other mover, if it is moving, must in turn be put in motion by another mover, and so on, and so on. This process cannot go on to infinity because then the sequence never would have gotten started. Therefore, it is necessary to arrive at a first mover who is unmoved.

The rationalist approach to proving God’s existence is called ontological from the Greek word for “being.” It means that an examination of the nature of God will prove he exists—just like an examination of the nature of a triangle proves the Pythagorean theorem.

The most famous version of the ontological argument comes to us from the 12th-century philosopher Anselm of Canterbury. Anselm began by defining God as “that being than which no greater can be conceived.” He went on to argue that God cannot just exist in the mind. If he did, then we could conceive of a greater god—namely, one that exists in the mind and in reality.

English philosopher Mary Astell offered a more straightforward ontological argument in the late 17th and early 18th centuries. She defined God as “that being who is by nature infinite in all perfections.” She defined a “perfection” as any quality that is better to have than not have. Her examples of perfections include wisdom, goodness, justice, intelligence, and power.