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Logic and Argumentation
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I. Introduction

When philosophers reflect on fundamental questions about the universe and about human existence and express their reflections in their writings, they use principles of logic and formulate arguments. A familiarity with the basic principles of logic and argumentation will help us understand philosophical writings more fully and will be useful in our own philosophical reflection and writing.

In philosophy, "argument" does not mean a quarrelsome dispute but, rather, a set of statements in which one or more statements are used to establish a further statement. The statements that are given to establish a point are called premises. The statement that the premises are intended to establish is called the conclusion. The mental process of moving from the premises to the conclusion is called inference. The branch of philosophy that systematically studies correct and incorrect inferences is called logic.

Logic studies the rules of inference from premises to conclusion, not the truth of the premises. To say that an inference is correct is to say that the premises lead to the conclusion. But even if the inference is correct, the conclusion may not be true if one or more of the premises are false. For example, from the premises that all Greeks were philosophers and that Pericles was a Greek, we can correctly infer that Pericles was a philosopher. But the first premise is false, and therefore the argument does not establish that the correctly inferred conclusion is true. Logic will not tell us whether any given premise is true; we must evaluate the truth of any given premise on the basis of knowledge derived from other sources.

The initial step in evaluating any philosophical argument is to identify the philosopher's premises and conclusion. We should keep in mind that authors do not always introduce their premises with indicator words, such as "because," "since," or "for," and they do not always mark their conclusions with indicator words, such as "therefore," "hence," and "so." Moreover, sometimes a premise-or even a conclusion-is not explicitly stated but only implied. Once we have identified the premises and the conclusion of an argument, we can examine the correctness of the inference and the truth of the premises. If the inference from the premises to the conclusion is incorrect, or if one or more of the premises are false, we know that the argument is faulty and does not establish the conclusion. If the premises are all true and if the inference is correct, we know that the premises do establish the conclusion.

Logic is the study of inference, and the two basic kinds of inference are deduction and induction. There are numerous forms of deductive and inductive arguments, but here we will consider only those forms that are used most frequently in the readings in the selections in Fifty Readings in Philosophy and that will be most useful to you in your own philosophizing and writing. (A discussion of additional forms of deduction and induction can be found in any standard textbook on logic.) We will examine common deductive arguments (Section II), common inductive arguments (Section III), and some techniques that philosophers frequently use to challenge arguments proposed by others (Section IV). Then, using examples from the readings in Fifty Readings in Philosophy, we will illustrate each kind of arguments and each kind of challenge (Section V). Finally, we will see how these principles can be used in writing a philosophy paper (Section VI).

II. Deductive Arguments

A deductive argument is one that is intended to lead from the premises (or from a single premise) to the conclusion in a necessary way. In other words, a deductive argument claims that the conclusion follows necessarily from the premises. If the conclusion of a deductive argument does follow necessarily from the premises, the argument is called a valid deductive argument. If the conclusion does not follow necessarily, the argument is an invalid deductive argument.

As we have already seen, the fact that the conclusion of an argument follows logically from its premises does not guarantee the truth of the conclusion. If all premises of a valid deductive argument are true, the conclusion is necessarily true. If one or more of the premises of a valid deductive argument are false, the conclusion is not necessarily true-it might be true, but if so its truth does not follow from the premises. Philosophers call a deductive argument that is valid and has only true premises a sound argument; if either of these conditions is not met, the argument is called unsound.
The kind of deductive argument most useful in analyzing philosophical writings and in doing our own philosophical reflection is the syllogism. A syllogism is a deductive argument with two premises and a conclusion. We will examine three kinds of syllogisms: hypothetical, disjunctive, and categorical.

A. Hypothetical Syllogisms

The two premises of a hypothetical syllogism are a two-part hypothetical premise (an "if-then" statement, a hypothesis) and a statement that affirms or denies one part of the hypothetical premise. The conclusion affirms or denies the other part of the hypothetical premise. The first part of the hypothetical statement (the "if" clause) is called the antecedent, and the second part (the "then" clause) is called the consequent. If we symbolize the antecedent by A, and the consequent by B, then the hypothetical premise "If A, then B" can be followed by any of four second premises: A, B, not A, or not B. This in turn produces four hypothetical syllogisms, two of them valid and two invalid.

The two valid forms are called modus ponens (a Latin phrase meaning "mode that affirms") and modus tollens ("mode that denies").

Modus ponens (also called "affirming the antecedent")

If A, then B. 
A. 
Therefore, B. 
Example:If this is a dog, then it is an animal.
 This is a dog.
 Therefore, this is an animal.
Modus tollens (also called "denying the consequent")

If A, then B. 
Not B. 
Therefore, not A. 
Example:If this is a dog, then it is an animal.
 This is not an animal.
 Therefore, this is not a dog.
The two invalid forms of the hypothetical syllogism are called "affirming the consequent" and "denying the antecedent."

Affirming the consequent

If A, then B. 
B. 
Therefore, A. 
Example:If this is a dog, then it is an animal.
 This is an animal.
 Therefore, this is a dog. (invalid-it might be an aardvark)
Denying the antecedent

If A, then B.  
Not A. 
Therefore, not B. 
Example:If this is a dog, then it is an animal.
 This is not a dog.
 Therefore, this is not an animal. (invalid-once again, it might be an aardvark)
These four forms, based on a hypothetical premise with an affirmative antecedent and an affirmative consequent, can be adapted to accommodate negative antecedents and consequents. In these alternate forms, if a double negative occurs in the second premise or the conclusion, it should be translated into an affirmative. The modus tollens form for the hypothetical premise "If X, then not Y," for example, would be "If X, then not Y; Y (not not Y); therefore, not X."

B. Disjunctive Syllogisms

In a disjunctive syllogism, the first premise joins two statements by "or" and asserts that at least one of the statements is true, but it does not specify which one(s). The individual statements in this premise are called the disjuncts. If the premise assumes that only one of the disjuncts is true (for instance, "Either the car was a Ford or it was a Toyota"), the disjunction means "either one or the other, but not both," and is called exclusive disjunction. If the premise allows both of the statements to be true (for example, "Either the car is out of gas or it has a defective fuel pump"), the disjunction means "either one or the other, or both" and is called inclusive disjunction. The person proposing a disjunctive syllogism may not state whether the disjunction is exclusive or inclusive; in this case, we should interpret the meaning as best we can. The second premise in a disjunctive syllogism affirms or denies one of the disjuncts, and the conclusion affirms or denies the other disjunct.

The following is a valid disjunctive syllogism:

Either A or B. (inclusive or exclusive disjunction)
Not B.
Therefore, A.
Example:Either the plot was boring or the acting was bad. (inclusive disjunction)
 The acting was not bad.
 Therefore, the plot was boring.
If the disjunction is inclusive, the following argument form (called "affirming the disjunct") is invalid:

Either A or B. (inclusive disjunction)
B.
Therefore, not A.
Example:Either the plot was boring or the acting was bad. (inclusive disjunction)
 The acting was bad.
 Therefore, the plot was not boring. (invalid-maybe the acting was bad and the plot was boring)

C. Categorical Syllogisms

The categorical syllogism is so named because it consists of categorical statements-that is, statements that affirm or deny a relation between categories (classes) of things. A categorical syllogism is a deductive argument that connects two classes of things by means of a third class. The three classes are called the subject term (S), the predicate term (P), and the middle term (M)-the middle term being so named because it stands between S and P and links them. One premise affirms or denies a connection between S and M, the other premise affirms or denies a connection between P and M, and the conclusion affirms or denies a connection between S and P. Categorical statements are typically put into one of the four standard forms listed below. These standard forms use the symbols A and B, rather than S and P, because the forms apply to all three statements of a categorical syllogism-the two premises, which contain S and M, and P and M; and the conclusion, which contains S and P. In these forms, "some" means "at least one."

All A are B. (All members of class A are included in class B.)
A refers to all the members of class A. B refers to just part of class B, since class B could contain members other than those in class A. The statement is affirmative because it asserts a relation between all the members of class A and some of the members of class B.
Some A are B. (Some members of class A are included in class B.)
A refers to part of class A. B refers to just part of class B, since class B could contain members other than "some A." The statement is affirmative because it asserts a relation between some of the members of class A and some of the members of class B. (Note that "Some A and B" does not logically require that some A are not B, although this is often implied in ordinary discourse.)
No A are B. (No members of class A are included in class B.)
A refers to all the members of class A. B refers to all the members of class B, since class A is excluded from the entirety of class B. The statement is negative because it denies a relation between all the members of class A and all the members of class B.
Some A are not B. (Some members of class A are not included in class B.)
A refers to part of class A. B refers to all the members of class B, since "some A" is excluded from the entirety of class B. The statement is negative because it denies a relation between some of the members of class A and all the members of class B. (Note that "Some A are not B" does not logically require that some A are B, although this is often implied in ordinary discourse.)
The basic valid affirmative form of the categorical syllogism is:
All M are P.
All S are M.
Therefore, all S are P.
Example:All primates are animals.
 All gorillas are primates.
 Therefore, all gorillas are animals.
The basic valid negative form is:
No M are P.
All S are M.
Therefore, no S are P.
Example: No birds are quadrupeds.
All sparrows are birds.
Therefore, no sparrows are quadrupeds.
A categorical syllogism is valid if it fulfills the four following conditions; if it violates one or more of these conditions, it is invalid. (For a justification of these rules, see any standard logic text.)
1.The middle term must refer to the entire class ("all") at least once.
Example of violation (with false conclusion):
 All mothers are females.
 All aunts are females.
 Therefore, all aunts are mothers.
Explanation: In each premise, "females" refers to just part of the class of females, but neither mothers nor aunts are all females.
2.If a term in the conclusion refers to the entire class, it must also do so in its premise.
Example of violation (with false conclusion):
 All senators are policy makers.
 All senators are fundraisers.
 Therefore, all fundraisers are policy makers.
Explanation: "Fundraisers" refers to part of the class in the second premise but to the entire class in the conclusion.
3. Both premises may not be negative.
Example of violation (with true conclusion):
 No apples are vegetables.
 Some vegetables are not beans.
 Therefore, some vegetables are not apples.
4. A negative premise requires a negative conclusion, and vice versa.
Example of violation (with true conclusion):
 Some teachers are not biologists.
 All biologists are scientists.
 Therefore, some scientists are teachers.

Although categorical syllogisms by definition make deductions about relationships among classes, they can be adapted to make deductions about individuals. This is done by replacing a term that designates an individual with an equivalent term that designates a class that has only one member. For example, the term "Socrates" can be replaced with "the class of all things identical to Socrates." Since it is cumbersome to write out such a translation, it is customary to use an individual term as a shorthand for the categorical term. It is also acceptable, as shorthand, to use an adjective as a term instead of a noun phrase-for example, to use "mortal" instead of "mortal being." In light of these two points, the following famous argument is a valid categorical syllogism:

All human beings are mortal.
Socrates is a human being.
Therefore, Socrates is mortal.

D. Other Deductive Arguments

Syllogisms are deductive arguments with two premises and a conclusion, but not all deductive arguments are of this kind. A deductive argument can have a single premise or three or more premises. For example, from the premise "No X is Y," we can validly conclude "No Y is X"; from the premises "A = B," "B= C," and "C = D," we can validly conclude "A = D." These and other additional forms of deductive arguments are used less frequently than syllogisms in philosophical writing, and they are not covered here.

III. Inductive Arguments

Whereas a deductive argument is intended to lead from the premises to the conclusion in a necessary way, an inductive argument is intended to lead from the premises to the conclusion in a probable way. An inductive argument does not claim (as a deductive argument does) that, if the premises are true, the conclusion must be true, but only that, if the premises are true, the conclusion is probably true. Since probability admits of degrees, inductive arguments are usually not classified as valid or invalid but rated according to strength or weakness. The strength of an inductive argument is determined by the degree of probability that the premises impart to the conclusion. To say that an inductive argument is strong is to say that if the premises are true, then it follows that the conclusion is probable; to say that it is weak is to say that if the premises are true, then it does not follow that the conclusion is probable. The more probable the premises of an inductive argument make the conclusion, the stronger the argument. If an inductive argument is strong and if all the premises are true, the argument is commonly called cogent. If the argument is weak and/or not all the premises are true, the argument can be called noncogent. Three kinds of inductive argument frequently used by philosophers are most plausible explanation, origins, and analogy.

A. Most Plausible Explanation

Due to the complexity and difficulty of most philosophical issues, many philosophical arguments are proposed not as deductively certain but simply as the most plausible explanation of those currently available for a certain set of facts. To use an example from science, evolutionary biologists accept the conclusion that the present traits of organisms resulted from the process of natural selection (the process in which changes in organisms that enable them to adapt to their environment are passed on to offspring) on the grounds that natural selection is a more plausible explanation for the data we have about organisms than are other explanations. The argument is inductive, not deductive, because it reaches its conclusion by eliminating other explanations that are held to be less adequate, while not claiming that natural selection is necessarily the correct explanation; the possibility is left open that someday a new hypothesis will be developed that will provide a better explanation than natural selection for the present traits of organisms.

B. Origins

Philosophers frequently inquire into the nature of something, and one approach to explaining the nature of a thing is to examine how it came to be. To understand the nature of political obligation, for example, one might speculate about how civil society and governments arose, what purposes they originally served, and how people became subject to the rules of government. To understand what consciousness is, one might examine how organisms first became conscious and what functions consciousness served. Such arguments are inductive, not deductive, because an account of origins can lead at best to a probable conclusion about the nature of something, not to a necessary conclusion. It remains possible that even a correct account of how a thing arose historically might not explain its nature accurately or sufficiently.

C. Analogy

An argument from analogy claims that, because one thing resembles another thing in one or more respects, it will also resemble it in some further respect. For instance, I can argue that, since I am an animal with a nervous system and I feel pain when I break a leg, and since a chimpanzee is an animal with a nervous system, therefore a chimpanzee feels pain when it breaks a leg. The argument is inductive because it is theoretically possible that the chimpanzee feels no pain. (It is also inductive to argue that, because I feel pain when I break a leg, other human beings feel pain when they break a leg, since it is theoretically possible that they do not.) Arguments from analogy are strong when the resemblance that the argument is trying to establish has an apparent relevance to the other resemblances mentioned, and when there are no apparently relevant dissimilarities between the two things being compared. The argument about a chimpanzee feeling pain is strong because being an animal with a nervous system has an apparent relevance to feeling pain, and the dissimilarities between me and a chimpanzee (size, weight, preferred diet, and so on) are not apparently relevant to feeling pain.

IV. Ways to Challenge Arguments

The two basic ways to challenge an argument, whether deductive or inductive, are to challenge the correctness of the inference from the premises to the conclusion and to challenge the truth of any of the statements constituting the argument (namely the premises and the conclusion). The general way to challenge the inference of a deductive argument is to show that the conclusion does not follow necessarily from the premises, whereas the general way to challenge the inference of an inductive argument is to show that the conclusion does not follow probably from the premises.

Philosophers use a variety of specific techniques to challenge the inference of an argument or the truth of the statements constituting the argument. We will examine four commonly used techniques: claim of inconsistency, claim of false analogy, counterexample, and unacceptable implications. The first two are used to challenge the correctness of the inference of an argument; the last two are ways to challenge the truth of the statements of the argument.

A. Claim of Inconsistency

One way to challenge the inference of an argument is to claim that the argument involves an inconsistency. The inconsistency might be within the argument itself-for example, the argument might have contradictory premises or have a conclusion that contradicts one of the premises. The inconsistency might also be within the person making the argument, in the sense that the person holds a belief that is not part of the argument but is inconsistent with either a premise or the conclusion of that argument. Since inconsistencies of either kind are rarely explicit, the technique of claiming inconsistency usually points out an implicit contradiction. For example, suppose someone has argued that the soul travels somewhere after we die and the argument contains no internal inconsistency. I might challenge the argument by asking the person whether he or she believes that the soul is a nonphysical entity and that nonphysical entities do not exist in space. If the person holds these beliefs, I might point out that they are inconsistent with the statement that the soul travels somewhere after death, since "travels somewhere" indicates a change in location. A demonstration of an inconsistency does not, of course, in itself show which of the inconsistent statements or beliefs is mistaken. To return to our example, if the person wants to maintain the view that the soul travels somewhere after we die, he or she can regain consistency by denying that the soul is nonphysical or by denying that nonphysical entities do not exist in space.

B. Claim of False Analogy

The inference in an argument from analogy can be challenged by denying the relevance of the similarities stated in the premises or by pointing out relevant dissimilarities that have been omitted. If someone argues that, because Smith's car is yellow, has four doors, and needs a tune-up, Jones's car must need a tune-up because it is yellow and has four doors, we can challenge the analogy on the basis that the similarities of color and number of doors are not relevant to the state of the engine. Suppose someone argues that Jones's car has a market value similar to that of Smith's car because the cars are the same make, model, and year. If it is also true that Jones's car, unlike Smith's, has very high mileage and has been involved in three major collisions, we can challenge the analogy on the basis that it ignores relevant dissimilarities.

C. Counterexample

If an argument makes a universal claim in a premise or in the conclusion, we can challenge the truth of that premise or conclusion by presenting an example that goes against that statement's universal claim. If someone uses the premise that all A are B, we can challenge that premise by presenting a counterexample of an A that is not B. We can use the same technique to challenge the conclusion of an argument. Suppose the conclusion of an argument is that it is always wrong to lie. One can challenge this conclusion by presenting an example of a lie that does not seem to be morally wrong. This counterexample might be the case of someone telling a lie to protect an innocent person from being killed by a deranged murderer.

D. Unacceptable Implications

An additional technique for challenging the truth of the premise or the conclusion of an argument is to show that the statement has one or more unacceptable implications. The implications may be unacceptable because they seem obviously false, or because they conflict with beliefs that are widely and deeply held. For example, suppose that the conclusion of an argument is that pleasure is always good. One can challenge this conclusion by pointing out that it implies that the pleasure a sadist derives from torturing and killing other people is good and by claiming that this implication is obviously false. (Whether the implication is, in fact, false can, of course, be debated.) An example of an implication that conflicts with widely and deeply held beliefs is the following. Suppose that the premise of an argument is that all our actions are the necessary result of preceding causes. One can challenge this premise by arguing that it implies that human beings have no free will and no moral responsibility for any of their actions (whether these are genuine implications of the premise can be disputed) and that these implications contradict the widespread and deep convictions that we do have free will and moral responsibility. (The fact that beliefs in free will and moral responsibility are generally and firmly held does not, of course, mean that they might not be mistaken.) The technique of showing an unacceptable implication of a statement is an inductive argument, not a deductive one, since it might be that an implication that seems obviously false is not actually false, or that a widely and deeply held belief that contradicts the implication is mistaken.

V. Illustrations from the Readings

All the varieties of deductive and inductive arguments and all the techniques for challenging an argument that we have examined are used in one or more of the selections in Fifty Readings in Philosophy. This section illustrates each kind of argument and each kind of challenge technique with examples taken from our readings.

A. Deductive Arguments

1. Hypothetical Syllogisms

Example 1 In his "Treatise on God," Thomas Aquinas presents a proof for the existence of God as the first efficient cause (an efficient cause is an agent that brings something into being or imparts change). To show that there cannot be an infinite regress of efficient causes (a series in which A is caused by B, B is caused by C, and so on, without end), he argues the following:

We cannot regress endlessly in the matter of efficient causes. . . . If we should regress endlessly in the case of efficient causes, there will be no first efficient cause, and thus there will be neither a final effect nor intermediate efficient causes, and this is clearly false. (p. 44)

This is a hypothetical syllogism in the form of modus tollens:

If there is an infinite regress of efficient causes, then there will be no first efficient cause, no final effect, and no intermediate efficient causes. It is not the case that there is no first efficient cause, no final effect, and no intermediate efficient causes.
Therefore, there is no infinite regress of efficient causes.

Example 2 René Descartes, in Meditations on First Philosophy, argues that not even a "malicious demon" could deceive him about the fact that he (Descartes) exists. For the purposes of this argument, Descartes assumes that a malicious demon is, in fact, deceiving him:

There is a deceiver of supreme power and cunning who is deliberately and constantly deceiving me. In that case too I undoubtedly exist, if he is deceiving me; and let him deceive me as much as he can, he will never bring it about that I am nothing so long as I think I am something. (p. 148)

This is a hypothetical syllogism in the form of modus ponens:

If a malicious demon is deceiving me, I exist.
A malicious demon is deceiving me.
Therefore, I exist.

2. Disjunctive Syllogisms

Example 1 In the Apology, his defense speech at his trial, Socrates uses a disjunctive syllogism to show the jury that, if he does corrupt the youth of Athens, as Meletus has charged, he does not do so intentionally (and therefore should not be indicted for this, but admonished and instructed in private):

[SOCRATES:] Are you bringing action against me here because I corrupt the youth intentionally, or unintentionally?
[MELETUS:] Intentionally, I say.
[SOCRATES:] How can that be, Meletus? Are you at your age so much wiser than I at mine that you recognize that evil men always do evil things to those around them, and good men do good, while I have reached such a pitch of folly that I am unaware that if I do some evil to those with whom I associate, I shall very likely receive some evil at their hands, so that I do such great evil intentionally, as you claim? I do not believe you, Meletus, and I do not think anyone else does either. (p. 12)

Put into proper syllogistic form, Socrates's argument is that, if he does in fact corrupt the youth:

Either I corrupt the youth intentionally or I corrupt the youth unintentionally.
I do not corrupt the youth intentionally.
Therefore, I corrupt the youth this unintentionally.

Example 2 Immanuel Kant argues in his Critique of Pure Reason that time is not an empirical concept (a concept derived from experience) but, rather, an a priori concept (a concept independent of experience):

Time is not an empirical concept that is somehow drawn from an experience. For simultaneity or succession would not themselves come into perception if the representation of time did not ground them a priori. (p. 185)

Kant's argument can be formulated as follows (with the first premise implied and the second premise defended in Kant's second sentence). The argument is valid because the first premise states an exclusive disjunction; if the disjunction were inclusive, the syllogism would commit the mistake of affirming the disjunct.

Either the concept of time is empirical or the concept of time is a priori.
The concept of time is a priori.
Therefore, the concept of time is not empirical.

3. Categorical Syllogisms

Example 1 In his proof for the existence of God in the Proslogion, Anselm defines God as "something than which nothing greater can be thought." He uses a categorical syllogism to prove that God exists in the understanding of the fool in the Book of Psalms, who says, "There is no God" (Psalms 15:1).

Even the fool must admit that something than which nothing greater can be thought exists at least in his understanding, since he understands this when he hears it, and whatever is understood exists in the understanding. (p. 35)

In proper syllogistic form, the argument is:

All things understood by the fool are things that exist in the fool's understanding. Something than which nothing greater can be thought is a thing understood by the fool. Therefore, something than which nothing greater can be thought is a thing that exists in the fool's understanding.

Example 2 In his Meditations, Descartes argues that his ideas of corporeal bodies are caused by actual corporeal bodies existing outside his mind and are not caused by God or some other creature transmitting these ideas into his mind. To show that these ideas are not transmitted by God or some other creature, he argues as follows:

Since God is not a deceiver, it is quite clear that he does not transmit the ideas to me either directly from himself, or indirectly via some creature. . . . For God has given me no faculty at all for recognizing any such source for these ideas; on the contrary, he has given me a great propensity to believe that they are produced by corporeal things. (p. 208)

This argument can be expressed in the following categorical syllogism (with the argument for the second premise presented in Descartes' second sentence).

No activities of God are deceptions.
All direct or indirect transmissions of the ideas of corporeal things into the mind are deceptions.
Therefore, no direct or indirect transmissions of the ideas of corporeal things into the mind are activities of God.

Example 3 In his "Letter from Birmingham Jail," Martin Luther King, Jr., addresses those who question the morality of his advocating civil disobedience as a means to attain civil rights for African-Americans. Drawing a distinction between just and unjust laws, he argues that we have a moral obligation to follow the former and a moral obligation to break the latter:

You express a great deal of anxiety over our willingness to break laws. . . . One has a moral responsibility to disobey unjust laws. . . . All segregation statutes are unjust because segregation distorts the soul and damages the personality. (p. 486)

King's argument can be formulated as a categorical syllogism (with the argument for the second premise appearing in King's third sentence, and with the conclusion implied).

All unjust laws are laws that we have a moral responsibility to disobey.
All segregation laws are unjust laws.
Therefore, all segregation laws are laws that we have a moral responsibility to disobey.

B. Inductive Arguments

1.Most Plausible Explanation

Example 1 In "The Dilemma of Determinism," William James explains why he prefers the doctrine of indeterminism (the view that the universe contains multiple possibilities) to the doctrine of determinism (the view that everything that happens in the universe, including every human action, is completely determined by the way things are now and cannot happen otherwise than it does). His reason is that indeterminism provides a more plausible framework than determinism for explaining the zest we feel when we choose what is morally good, the self-reproach we feel when we choose what is morally bad, and the regret we feel when morally bad acts occur in the world.

What interest, zest, or excitement can there be in achieving the right way, unless we are enabled to feel that the wrong way is also a possible and a natural way-nay, more, a menacing and an imminent way? And what sense can there be in condemning ourselves for taking the wrong way, unless we need have done nothing of the sort, unless the right way was open to us as well? I cannot understand the willingness to act, no matter how we feel, without the belief that acts are really good and bad. I cannot understand the belief that an act is bad, without regret at its happening. I cannot understand regret without the admission of real, genuine possibilities in the world. (p. 284)

Example 2 In "The Case for Physicalism," David Carruthers defends the "causal closure of physics," according to which all mental events are caused by physical events. He argues that the most plausible cause of a mental event is a physical event.

What reason do we have for believing in the causal closure of physics? This is not something which can be proved (least of all by thought alone, of course). But for some centuries it has been a successful methodological assumption of scientific inquiry. Scientists work under the assumption that processes in physics brook no interference from higher levels of causation. Whenever they come across physical phenomena which cannot presently be explained in physical terms, instead of postulating causation by élan vital (a supposed independent biological life-force), or causation by ectoplasm (a supposed independent psychic force), or whatever, they look deeper into the physical mechanisms. In many such cases this deeper look has proved successful; and in all such cases physicalistic scientific inquiries continue to make progress. This gives us good reason to think that the scientific methodology is correct, and that physics is indeed closed. (p. 211)

2. Origins

Example 1 In his treatise Leviathan, Thomas Hobbes explains the nature of justice by describing its origin. He maintains that political society arose when individuals left the "state of nature" and entered into a covenant with each other, transferring their rights to a common power. One of the laws of nature is that we must keep our covenants, and this law accounts for the existence of justice and reveals its nature.

[It is a law of nature] that men perform their covenants made-without which, covenants are vain and but empty words. . . .
And in this law of nature consists the fountain and original [origin] of justice. For where no covenant has preceded, there has been no right transferred, and every man has a right to every thing; and consequently no action can be unjust. But when a covenant is made, then to break it is unjust; and the definition of injustice is no other than the nonperformance of a covenant. And whatsoever is not unjust, is just. (p. 442)

Example 2 Daniel C. Dennett, in "The Origins of Selves," seeks to discover the nature of the self by examining how, in the course of evolution, selves came to be. He argues that selves arose when organisms began seeking self-preservation and that the self, in the most basic sense, is an organization that draws boundaries between the organism and what is not the organism.

The original distinction between self and other is a deep biological principle; one might say it is the deepest principle, for biology begins in self-preservation-in the emergence of entities (the simplest replicators) who resisted destruction and decay . . . and passed on their capacity to do this to their descendants. . . .
The origin of complex life forms on this planet was also the birth of the most primitive sort of self, whatever sort of self is implied by the self-regard that prevents the lobster, when hungry, from eating itself. . . .
A minimal self is not a thing inside a lobster or a lark, and it is not the "whole lobster" or the "whole lark" either; it is something abstract which amounts just to the existence of an organization which tends to distinguish, control, and preserve portions of the world, an organization that thereby creates and maintains boundaries. (pp. 256-58)

3. Analogy

Example 1 In the Apology, his defense speech at his trial, Socrates uses an analogy to show the jury that his accuser Meletus contradicts himself by stating that Socrates believes in divinities but does not believe in gods. Just as anyone who believes that there are mules must believe that there are horses and asses, so anyone who believes that there are divinities must believe that there are gods.

[SOCRATES:] If divinities are children of gods, some born illegitimately of nymphs or others of whom this is said, who could possibly believe that there are children of gods, but not gods? It would be as absurd as believing that there are children of horses and asses (namely mules) without believing there are horses and asses. (p. 14)

Example 2 In his book Natural Theology, William Paley uses an analogy to show that the eye is the product of intelligent design: Just as a telescope is designed by someone to extend vision, so the eye is designed by someone (namely God) to see.

There is precisely the same proof that the eye was made for vision, as there is that the telescope was made for assisting it. They are made upon the same principles, both being adjusted to the laws by which the transmission and refraction of light rays are regulated. (p. 61)

C. Techniques for Challenging Arguments

1. Claim of Inconsistency

Example 1 In Plato's dialogue Euthyphro, Socrates asks the priest Euthyphro to define piety and impiety. At one point Euthyphro defines piety as what is dear to the gods and impiety as what is not dear to the gods. Socrates then points out to Euthyphro that he (Euthyphro) also believes that the gods disagree about things such as justice, beauty, and goodness. Socrates then points out that this belief, when combined with Euthyphro's original definitions, leads to contradictory conclusions.

EUTHYPHRO: What is dear to the gods is pious, and what is not is impious. . . .
SOCRATES: According to [what you have subsequently admitted], my good Euthyphro, different gods consider different things to be just, beautiful, ugly, good, and bad. . . . And they like what each one of them considers beautiful, good, and just, and hate the opposite of these?
EUTHYPHRO: Certainly.
SOCRATES: But you say the same things are considered just by some gods and unjust by others. . . . [So] the same things then are loved by the gods and hated by the gods. . . .
EUTHYPHRO: It seems likely.
SOCRATES: And the same things would be both pious and impious, according to this argument?
EUTHYPHRO: I'm afraid so. (pp. 113-14)

Example 2 Anselm, as we saw in a previous example, defines God as "something than which nothing greater can be thought" and contends that God exists in the understanding. He then argues that anyone who denies that God exists is guilty of inconsistency, because the person would hold that something than which nothing greater can be thought exists in the understanding but not also in reality. This is inconsistent because, if this being that exists in the understanding does not also exist in reality, it is not something than which nothing greater than can be thought, because it is possible to think of a greater being-namely one that also exists in reality.

That than which a greater cannot be thought cannot exist only in the understanding. For if it exists only in the understanding, it can be thought to exist in reality as well, which is greater. So if that than which a greater cannot be thought exists only in the understanding, then that than which a greater cannot be thought is that than which a greater can be thought. But that is clearly impossible. (p. 35)

2. Claim of False Analogy

Example 1 In Hume's Dialogues Concerning Natural Religion, the fictional character Cleanthes presents an argument from analogy (similar to the one given by Paley, which we examined previously): Just as the design of artifacts, such as ships and cities, shows that they were produced by intelligent beings, so the design of the universe shows that it was produced by an intelligent being (namely God). In the following passage from the Dialogues, the character Philo rejects Cleanthes' argument from analogy because it fails to note a relevant difference between artifacts and the universe-that we have experienced the origin of the former, but not of the latter.

When two species of objects have always been observed to be conjoined together, I can infer, by custom, the existence of one wherever I see the existence of the other; and this I call an argument from experience. But how this argument can have place where the objects, as in the present case, are single, individual, without parallel or specific resemblance, may be difficult to explain. And will any man tell me with a serious countenance that an orderly universe must arise from some thought and art like the human, because we have experience of it? To ascertain this reasoning, it were requisite that we had experience of the origin of worlds; and it is not sufficient, surely, that we have seen ships and cities arise from human art and contrivance. (p. 51)

Example 2 In Existentialism Is a Humanism, Jean-Paul Sartre explains that theists hold that there is a human nature on the grounds that, just as an artifact (a knife, for example) has a nature because a human artisan conceives the object before manufacturing it, so human beings have a nature because God is the divine artisan who conceives of human beings before creating them. But for an atheistic existentialist like Sartre, there is not God and hence no divine artisan and no human nature.

When we think of God the Creator, we usually conceive of him as a superlative artisan. . . . Thus the concept of man, in the mind of God, is comparable to the concept of the paper-knife in the mind of the manufacturer: God produces man following certain techniques and a conception, just as the craftsman, following a definition and a technique, produces a paper-knife. Thus each individual man is the realization of a certain concept within the divine intelligence. . . .
If man as existentialists conceive of him cannot be defined, it is because to begin with he is nothing. He will not be anything until later, and then he will be what he makes of himself. Thus, there is no human nature since there is no God to conceive of it. (pp.387-88)

3. Counterexample

Example 1 In "Freedom and Determinism," Richard Taylor uses the method of counterexample to challenge soft determinism, the doctrine that, although all our actions are causally determined, some of them are also free-namely those that are not externally impeded and are causally determined by inner states of the agent, such as volitions. Taylor gives an example of behavior that fits this description but seems clearly not to be free.

Suppose that an ingenious physiologist can induce in me any volition he pleases, simply by pushing various buttons on an instrument to which, let us suppose, I am attached by numerous wires. All the volitions I have in that situation are, accordingly, precisely the ones he gives me. By pushing one button, he evokes in me the volition to raise my hand; and my hand, being unimpeded, rises in response to that volition. By pushing another, he induces the volition in me to kick, and my foot, being unimpeded, kicks in response to that volition. . . .
This is the description of a man who is acting in accordance with his inner volitions, a man whose body is unimpeded and unconstrained in its motions, these motions being the effects of those inner states. It is hardly the description of a free and responsible agent. (p. 297)

Example 2 Thomas Nagel in his article "What Is It Like to Be a Bat?" uses a counterexample to challenge psychophysical reductionism, the view that the mind can be "reduced to" (explained fully in terms of) the body. His counterexample is subjective experience, which occurs from a particular point of view and seems incapable of being captured by objective scientific analysis.

We appear to be faced with a general difficulty about psychophysical reduction. In other areas the process of reduction is a move in the direction of greater objectivity, toward a more accurate view of the real nature of things. This is accomplished by reducing our dependence on individual or species-specific points of view toward the objective of investigation. . . . The less it depends on a specifically human viewpoint, the more objective is our description. . . .
Experience itself, however, does not seem to fit the pattern. The idea of moving from appearance to reality seems to make no sense here. . . . Certainly it appears unlikely that we will get closer to the real nature of human experience by leaving behind the particularity of our human point of view. . . . If the subjective character of experience is fully comprehensible only from one point of view, then any shift to greater objectivity-that is, less attachment to a specific viewpoint-does not take us nearer to the real nature of the phenomenon; it takes us farther away from it. (pp. 225-26)

4. Unacceptable Implications

Example 1 Blaise Pascal in his Pensées considers the argument that, since it is disputed whether the soul is immortal, we should not be concerned about this issue but simply ignore it and live for immediate pleasure. He challenges the conclusion of this argument by pointing out that it has the unacceptable implication that, if we follow the advice it gives, we risk an afterlife of eternal misery because the soul may be immortal and be eternally punished for seeking a life of immediate pleasure. This implication is unacceptable because it conflicts with the widespread and strong belief that it is not rational to ignore a topic that is crucial to our personal (and perhaps eternal) well-being.

Let us then judge . . . those who live without a thought for the end of life, drifting wherever their inclinations and pleasures may take them, without reflection or anxiety, as if they could annihilate eternity by keeping their minds off it, concerned solely with attaining instant happiness. . . .
The consequences are undeniably terrible. They risk an eternity of wretchedness; whereupon, as if the matter were not worth their trouble, they omit to consider . . . whether the proofs [for immortality] are strong or weak. The proofs lie before their eyes, but they refuse to look, and in this state of ignorance they choose to do everything necessary to fall into this calamity, if it exists, to wait for death before testing the proofs. (p. 428)

Example 2 In "The Challenge of Cultural Relativism," James Rachels and Stuart Rachels present their reasons for rejecting the theory that there are no absolute standards of right and wrong because all moral values are determined by and relative to individual cultures. One of their reasons is that some of the implications of this theory contradict widely and deeply held beliefs.

Suppose we took [cultural relativism] seriously. What would be some of the consequences? . . .
The Chinese government has a long history of suppressing political dissent within its own borders. At any given time, thousands of political prisoners in China are doing hard labor, and in the Tiananmen Square episode of 1989, Chinese troops slaughtered hundreds, if not thousands, of peaceful protesters. Cultural relativism would preclude us from saying that the Chinese government's policies of oppression are wrong. . . .
Suppose a resident of India wonders if her society's caste system-a system of rigid social hierarchy-is morally correct. All she has to do is ask whether this system conforms to her society's moral code. If it does, there is nothing to worry about, at least from a moral point of view. This implication of cultural relativism is disturbing because few of us think that our society's code is perfect-we can think of all sorts of ways in which it might be improved . . .
If cultural relativism is correct, can we legitimately think [that there is] moral progress? Progress means replacing a way of doing things with a better way. But by what standard do we judge the new ways as better? If the old standards were in accordance with the social standards of their time, then cultural relativism would say it is a mistake to judge them by the standards of a different time. (p. 402)

VI. Application to Writing Papers

Writing philosophy papers is one of the best ways to develop the skill of philosophizing, and your instructor is likely to assign one or more papers. These assignments can take various forms. You may be asked, for example, to explain what an author said, to compare and contrast the views of two authors, to discuss different interpretations of a philosophical work, to evaluate the position of an author, or to present and defend your own position on a philosophical topic. But whatever your specific paper assignment, it will almost surely require you to apply principles of logic and argumentation. To explain what an author said, or to compare and contrast the positions of two authors, you must be able to identify the premises and conclusions of the arguments presented. To discuss others' interpretations of an author, it is necessary to lay out the arguments given to support those interpretations. To evaluate the views of an author, you will need to judge the truth of the author's premises and to determine the legitimacy of the inference to the conclusion. To present and defend your own position on a topic, you will need to make your premises clear, explain why you find them plausible, and show that they establish your conclusion.

This final section offers suggestions on how to apply to your own philosophical writing the principles of logic and argumentation set forth in Sections II, III, and IV. The first three parts of this section discuss the application of these principles to, respectively, the exposition (explanation) of an author's position, the evaluation of an author's position, and the presentation and defense of your own views on an issue. The final part gives suggestions for structuring a philosophy paper.

A. Exposition

When giving an exposition of a philosopher's views, it is important to do more than simply state the author's conclusions. Philosophers present arguments to defend their views, and an explanation of an author's position requires an articulation of the arguments given to support that position.

The first step in writing an exposition is to determine which specific position of the author your paper assignment asks you to explain. Your exposition should focus on that specific position, not cover material not directly pertinent to it. For example, if you are asked to explain Aquinas's proof for the existence of God based on motion (pp. 43-443), you need not-and should not-explain the preceding sections of Aquinas's treatise that discuss whether the existence of God is self-evident or the four additional proofs for the existence of God that follow the proof from motion. If you cover these additional arguments by Aquinas, you will distract the reader from the main point of your paper.

Once you are clear on which specific position you need to explain, you need to analyze the author's basic argument. Since the position is the conclusion of an argument, it will be based on premises. You need to ask yourself the following questions: What are the main premises? Are they all explicit, or are some implicit? Is the argument deductive or inductive? What specific form of deductive or inductive argument is used? If the argument is inductive, what degree of probability does the author attribute to the conclusion?

After you have established the logical form of the basic argument, see if the author proposes secondary arguments (arguments that support the premises of the basic argument). For example, one of Anselm's premises in his proof for the existence of God is that God exists in the understanding, and this premise (as we have seen) is established by a categorical syllogism. The author may then propose additional arguments to establish the premises of the secondary argument. The author will not carry back the process of establishing premises indefinitely, and your exposition should point out where the process stops. Anselm, for example, does not give a proof to show that it is greater to exist in the understanding and in reality than it is to exist in the understanding alone. (He seems to think that this is self-evident, but keep in mind that what is self-evident to one philosopher may not be self-evident to another.)

In your exposition be sure to document your statements about what the author says-not only direct (verbatim) quotations but also indirect quotations (paraphrases). This will enable your instructor, and any other readers of your paper, to verify that the author said what you assert the author said. If your exposition includes points that are implicit but not explicit in the reading (for example, an assumed premise or a specific form of argument), you need not document the passages that led you to attribute these implicit points to the author unless there is a special reason to do so (if your interpretation is controversial, for instance). There are a number of formats for documentation, and in your paper you should use one approved by your instructor.

B. Evaluation

A paper assignment on an author's position is likely to ask you not only to explain what the position is but also to evaluate it. Once you have articulated the argument the author makes to support his or her position, you can proceed to evaluate the argument. The evaluation of an argument has two components: determining whether the premises establish the conclusion and assessing the truth of the premises.

To judge whether the author's premises establish the conclusion, first you need to determine whether the argument is deductive or inductive. If the argument is deductive, put the argument in proper logical form. (Most of the deductive arguments you will encounter can be put into one of the syllogistic forms described in Section II). Once the argument in is logical form, check it for validity. If the conclusion does not follow necessarily from the premises, the argument is invalid and it fails (although the conclusion might be true). If the argument is inductive, see if the conclusion follows probably from the premises. If the conclusion is probable, the argument is strong; if not, the argument is weak and should be rejected. Since strength and weakness admit of degrees, your evaluation of an inductive argument should include a statement of how strong or weak the argument is.

Assessing the truth of the premises is not always a simple matter. To evaluate premises you should consider not only the arguments given by the author to support them but also other relevant information that you have or can find. Since philosophical matters are usually controversial, you may not be certain whether the author's premises are true or not. In this case you should state whether you think it is likely that the premises are true and give reasons for your judgment. If you believe that one or more of the premises of the author's argument are false, or probably false, you have good reason to reject the argument.

If the argument you are examining is deductive, is valid, and has all true premises, you can evaluate the argument as sound; if the argument is invalid and/or if any of the premises are false, the argument is unsound. If the argument is inductive, is strong, and has all true premises, the argument is cogent; if the argument is weak and/or if any of the premises are false, the argument is noncogent.

C. Defending Your Own Position

Your paper assignment may ask you to present and defend your own position on a philosophical topic. For example, you may be asked whether there is a self, whether human beings have free will, or whether cultural relativism is true. The selections in Fifty Readings in Philosophy, your instructor's lectures, your classroom discussions, reflection on your own experience, and library and other research can all contribute to your understanding of the topic and to your personal answer to the question. But the quality of your paper will depend primarily on the arguments you give to support your answer, not on the answer itself. Few philosophy instructors would claim to have the definitive answer to any fundamental philosophical question (and therefore could hardly grade your paper on whether you give the right answer), and even fewer expect their students to demonstrate a definitive answer in their papers. And although it can be illuminating to cite the opinions of other philosophers when defending your own position, what is important for the purposes of your paper is not the fact that a philosopher (perhaps a famous one) holds a particular view but the arguments he or she gives to support it. Thus, if you cite authorities in your paper, be sure to explain how they defend their views.

To defend your position on a philosophical topic, you should be clear in your own mind whether your argument is deductive or inductive, which specific kind of deductive or inductive argument you are using, what your premises are, and the reasons you have for accepting these premises. Although it is not necessary to use the terminology of logic in writing your paper ("premise," "deduction," "syllogism," "analogy," "validity," "soundness," and so on), you should follow logical principles when constructing and presenting the argument that supports your position.

Since nearly every philosophical position is controversial, there are likely to be significant challenges that might be raised against the view that you defend in your paper. When you are thinking about your topic and formulating your own position, it is important to consider possible challenges to your position and whether you can respond adequately to them (if not, you may wish to reevaluate your position in light of those challenges). When you present your arguments for your position in your paper, you will strengthen your case if you anticipate strong challenges and respond to them in your paper. A challenge can come from an argument that a philosopher or another thinker has already raised against the position you are defending, or it can be one that you have thought of yourself. If it comes from someone else, you should, of course, document its source. When presenting the challenge, make clear what kind of argument it is and identify its premises and conclusion. To respond to the challenging argument, you can question the legitimacy of its inference from the premises to the conclusion, or the truth of any of its statements (premises or conclusion). To do this you can use one of the four techniques described in Section IV (claim of inconsistency, claim of false analogy, counterexample, unacceptable implications) or question in some other way the inference or one of the statements of the challenging argument.

D. Structuring Your Paper

The structure of your paper will depend, of course, on the kind of paper that has been assigned. For example, a wholly expository paper will differ from one in which you explain and evaluate a theory. A paper in which you compare and contrast two authors will take a form different from one in which you present and defend your own view of a particular topic. But whatever the assignment, your paper should begin with an introduction. The introduction should inform the reader of the topic (subject matter) of the paper, explain the importance of the topic, give an overview of your paper, and state clearly your thesis (the position that you defend). Do not confuse a topic with a thesis. For example, the statement "In this paper I will present my views on whether free will exists" describes a topic but does not state a thesis. By contrast, "In this paper I will contend that free will is an illusion" is a thesis statement. Do not worry that by stating your thesis at the beginning of your paper you will lessen its interest by giving away the conclusion of your argument: What is of primary interest in a philosophy paper is how a thesis is defended, not what the thesis itself is. You actually increase interest by stating your thesis in your introduction, because readers can then direct their attention to seeing how all the parts of your paper contribute to your defense of your thesis.

In addition to having an introduction, all philosophy papers should end with a conclusion. "Conclusion" here does not mean the logical conclusion of your premises ("conclusion" in that sense is the thesis of your paper) but, rather, a brief summary of your entire paper, including a restatement of your thesis (though not necessarily a verbatim repetition of the thesis as stated in your introduction). Your conclusion can also indicate some interesting implications of the thesis you have established-for example, if you have argued that there is no free will, you can point out that you had to write the paper exactly as you did. You can also point out, as topics for future exploration, some philosophical questions raised by your thesis or some philosophical issues that could be reexamined in light of your thesis.

The content and order of the middle sections of your paper will be dictated by the assigned topic and the particular approach to take. Unless your paper is wholly expository, or is a comparison and contrast of two or more views, it will include arguments defending a particular philosophical position. Whatever your direct arguments, your defense will usually be stronger and more convincing to the reader if you present and respond to plausible challenges to your position.

The papers I assign in my own philosophy courses typically require students to take a stand on a position presented by an author in Fifty Readings in Philosophy., and part of the assignment is to present the best challenge (or two challenges) the student can think of against that position. The challenge may or may not be taken from another author (for example, from another author in Fifty Readings in Philosophy.), but if it is, the student must document the source. I ask students to structure these papers as follows:

I. Introduction (must include a thesis statement)
II. Exposition (an explanation of the author's position)
III. Challenge (the best argument against the author's position)
IV. Defense of thesis (an argument why the author's position is correct or incorrect)
V. Conclusion (must include a restatement of the thesis, though not necessarily verbatim)

I explain to my students that Parts II and III are like two opposing speeches in a debate. Part II should present the author's argument as clearly and persuasively as possible, with no evaluative comments on its soundness or cogency. Part III should give an opposing argument, again without any evaluative comments. The evaluation of the arguments in Parts II and III comes in Part IV, when students give their arguments for accepting or rejecting the position of the author. If students agree with the author, they must explain why the challenge set forth in Part III does not hold. If they agree with the challenge, they must elaborate on the challenge and explain why they think the author could not respond adequately to it. Part IV is the heart of the paper: The function of Parts I, II, and III is to set the stage for Part IV, and the function of Part V is to summarize how Part IV built on the material in Parts II and III to defend the thesis of the paper.

Philosophy papers can be organized effectively in many ways. But no matter what the topic or what the structure, the key element in nearly any philosophical paper is argumentation. And the principles of logic and argumentation presented and illustrated here should be useful to you when you write the papers assigned in your philosophy course.








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