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Philosophy studies fundamental questions about reality, knowledge, morality, and meaning. Philosophers use arguments to support their claims and to persuade others of their views. But what is an argument in philosophy, and how can you analyze and evaluate it?
An argument in philosophy is not a quarrel or a dispute. It is a series of statements meant to provide reasons for accepting a conclusion. The conclusion is the main point that the arguer wants to establish, while the reasons are called premises. The premises are supposed to support or justify the conclusion logically.
For example, consider this argument:
- If someone lives in San Francisco, then they live in California.
- If someone lives in California, then they live in the United States.
- Hassan lives in San Francisco.
- Therefore, Hassan lives in the United States.
This argument concludes with the last statement: Hassan lives in the United States. The premises are the first three statements, which provide reasons for accepting the conclusion. The argument is valid, which means that if the premises are true, the conclusion must also be true.
But how can you tell if an argument is valid or not? And how can you tell if the premises are true or not? These are the questions that argument analysis and evaluation aim to answer. Argument analysis is the process of identifying the structure and components of an argument, while argument evaluation is the process of assessing the quality and strength of an argument.
How to Analyze an Argument
The first step in analyzing an argument is identifying the conclusion and the premises. Sometimes, the conclusion and the premises are explicitly stated, and the arguer uses words or phrases that indicate them. For example, the arguer may use words like “therefore,” “hence,” “so,” or “thus” to signal the conclusion, and words like “because,” “since,” “for,” or “given that” to signal the premises. Here are some examples of arguments with explicit conclusions and premises:
- All humans are mortal. Socrates is human. Therefore, Socrates is mortal.
- Since it is raining, you should take an umbrella.
- Smoking causes lung cancer. Therefore, you should quit smoking.
However, the conclusion and the premises are sometimes not explicitly stated, and the arguer uses no indicator words or phrases. In that case, you have to infer the conclusion and premises from the statements’ context and meaning. Here are some examples of arguments with implicit conclusions and premises:
- You look tired. You should get some rest. (The conclusion is “You should get some rest,” and the premise is “You look tired.”)
- Cats are better than dogs. They are cleaner, quieter, and more independent. (The conclusion is “Cats are better than dogs,” and the premises are “They are cleaner, quieter, and more independent.”)
- It’s either raining or snowing. It’s not snowing. (The conclusion is “It’s raining,” and the premises are “It’s either raining or snowing” and “It’s not snowing.”)
The second step in analyzing an argument is to identify the type and form of the argument. There are two main types of arguments: deductive and inductive. A deductive argument is an argument that claims to provide conclusive or certain support for its conclusion. If a deductive argument is valid and has true premises, then its conclusion must be true as well. However, if a deductive argument is invalid or has false premises, then its conclusion may be false. Here are some examples of deductive arguments:
- All men are mortal. John is a man. Therefore, John is mortal. (This is a valid deductive argument with true premises and a true conclusion.)
- All dogs are mammals. All mammals are reptiles. Therefore, all dogs are reptiles. (This is an invalid deductive argument with false premises and conclusions.)
- All roses are red. This flower is a rose. Therefore, this flower is red. (This is a valid deductive argument with a true premise, a false premise, and a false conclusion.)
An inductive argument is an argument that claims to provide probable or likely support for its conclusion. If an inductive argument is strong and has true premises, then its conclusion is probably true. However, if an inductive argument is weak or has false premises, then its conclusion may be false. Here are some examples of inductive arguments:
- Most birds can fly. Tweety is a bird. Therefore, Tweety can fly. (This is a strong inductive argument with a true premise and a true premise, and a probably true conclusion.)
- Most cats like milk. Garfield is a cat. Therefore, Garfield likes lasagna. (This is a weak inductive argument with a true premise, a false premise, and a probably false conclusion.)
- The sun has risen every day so far. Therefore, the sun will rise tomorrow. (This is a strong inductive argument with a true premise and a probably true conclusion.)
The form of an argument is how the premises and the conclusion are arranged and connected. Different forms of arguments include modus ponens, modus tollens, disjunctive syllogism, hypothetical syllogism, categorical syllogism, etc. Each argument has a specific pattern and rules determining its validity or strength. For example, modus ponens is a form of argument that has the following pattern:
- If P, then Q.
- P.
- Therefore, Q.
This form of argument is always valid, regardless of the content of P and Q. Here are some examples of modus ponens arguments:
- If it is raining, then the streets are wet.
- It is raining.
- Therefore, the streets are wet.
- If you study hard, then you will pass the exam.
- You study hard.
- Therefore, you will pass the exam.
- If you are a human, then you are mortal.
- You are a human.
- Therefore, you are mortal.
The third step in analyzing an argument is identifying hidden or unstated assumptions or premises. Sometimes, an argument may not explicitly state all the premises needed to support the conclusion. These premises are called hidden or unstated assumptions or premises, and they are often implied or taken for granted by the arguer. For example, consider this argument:
- You should not eat meat. It is cruel to animals.
- The conclusion of this argument is “You should not eat meat,” and the explicit premise is “It is cruel to animals.” However, this premise alone is not enough to support the conclusion. A hidden or unstated premise is needed to make the argument valid or strong. This premise says, “You should not do anything cruel to animals.” Without this premise, the argument is invalid or weak because it does not show why being cruel to animals is a reason not to eat meat.
To identify hidden or unstated assumptions or premises, you can ask yourself questions like:
- What is the arguer taking for granted or assuming?
- What is the arguer not saying or leaving out?
- What additional reasons or evidence are needed to support the conclusion?
How to Evaluate an Argument
The fourth step in analyzing an argument is to evaluate the argument. Evaluating an argument means assessing whether the argument is good or bad, sound or unsound, strong or weak, or convincing. To evaluate an argument, you need to consider two main criteria: the truth of the premises and the validity or strength of the argument.
The truth of the premises is the degree to which the premises are true or false, based on facts, evidence, or common sense. To evaluate the truth of the premises, you need to check the sources, reliability, and accuracy of the information the arguer uses to support the premises. You must also consider any possible objections, counterexamples, or alternative explanations that may challenge or undermine the premises. For example, consider this argument:
- Smoking causes lung cancer. Therefore, you should quit smoking.
The premise of this argument is “Smoking causes lung cancer,” and the conclusion is “You should quit smoking.” To evaluate the truth of the premise, you need to examine the scientific studies, statistics, and data that show the causal link between smoking and lung cancer. You also need to consider any possible objections, such as the fact that not all smokers get lung cancer or that there may be other factors that contribute to lung cancer, such as genetics or environmental pollution.
The validity or strength of the argument is the degree to which the argument provides conclusive or probable support for the conclusion based on logic and reasoning. To evaluate the validity or strength of the argument, you need to check the form and structure of the argument and see if the premises logically imply or suggest the conclusion. You must also consider any possible fallacies, errors, or flaws in the argument that may affect its validity or strength. For example, consider this argument:
- All dogs are mammals. All mammals are reptiles. Therefore, all dogs are reptiles.
The premise of this argument is “All dogs are mammals” and “All mammals are reptiles”, and the conclusion is “All dogs are reptiles.” To evaluate the argument’s validity, you need to check the form and structure of the argument and see if the premises logically imply the conclusion. In this case, the argument has the form of a categorical syllogism, which is a type of deductive argument that has the following pattern: