Argumentation, whether in philosophy or elsewhere, often can be analyzed or "broken down" into a series of moves. While sometimes you will run across a "move" that is out of the ordinary, much argumentation reduces to a reasonably small set of standard moves. While this is not the place to provide you with an exhaustive repertoire of such moves, I will list and discuss several which you will find cropping up as you explore arguments. Each of these moves may be expressed as a valid argument form. Any substitution instance of one of these argument forms will be such that if the premises are true, the conclusion will be true as well. That is, each of these moves is truth preserving. There is no overarching pattern to my selection of these forms. I have simply chosen ones I feel are common in philosophical argument.

Modus Ponens:

        The first form I wish to introduce is called "modus ponens," but don't let the Latin throw you off. It is really quite straightforward:

	If p, then q.
	p.
	q.
	Example:
	If there is no God, then life is meaningless.
	There is no God.
	Life is meaningless.

        The premises may or may not be true, and in any case at least the first premise requires clarification, but the argument is valid. That is to say, if the premises are true, the conclusion must also be true.

        No philosopher would offer this as the whole of what is to be said on this issue, but this example of modus ponens could provide a convenient summary of someone's philosophical position on this issue and a starting point for further exploration and critique.

Modus Tollens:

        Modus tollens is another basic argument form which has a conditional statement as its key premise.

	If p, then q.
	It is not the case that q.
	It is not the case that p.
	Example:
	If an all powerful and all merciful God exists, then there is no evil in the world.
	It is not the case that there is no evil in the world.
	It is not the case that an all powerful and all merciful God exists.

        Again the first premise, at least, is hotly debated. But the argument is valid: if the premises are true, so is the conclusion.

Pure Hypothetical Syllogism:

        Pure hypothetical syllogism is so-called because it consists of two premises and a conclusion (and so is by definition is a syllogism) and, unlike the previous two forms, both of its premises (and its conclusion) are conditional (or, in other words, "hypothetical"--in one technical sense of the term) statements.

	If p, then q.
	If q, then r.
	If p, then r.
	Example:
	If all actions are causally determined, then no actions are free.
	If no actions are free, then no one is responsible for anything they do.
	If all actions are causally determined, then no one is responsible for anything they do.

        Once again the premises require both clarification and defense and this is but an overall outline (or perhaps a piece) of an argument that might be made. But this much is valid.

        (For another example of an argument in the form pure hypothetical syllogism see "Identifying and Formulating Arguments.")

Disjunctive Syllogism:

        The next form, called "disjunctive syllogism," works by elimination of possibilities. If there are only two possibilities and then one is ruled out, the other must be actual.

	Either p or q.
	It is not the case that p.
	q.
	Example:
	Either my idea of God is generated from my own mind or something exists which is other than my mind.
	It is not the case that my idea of God is generated from my own mind.
	Something exists which is other than my mind.

        This is a fragment of Descartes' famous argument in the Third Meditation that he is not alone in the universe.

Constructive Dilemma:

        Now we move on to slightly more complex argument forms. The first is called "constructive dilemma." It involves multiple possibilities (listed in the first premise), but these need not be unpleasant possibilities (as the name "dilemma" might suggest).

	Either p or q.
	If p, then r.
	If q, then s.
	Either r or s.
	Example:
	Either the evil in the universe is contrary to God's design or the evil in the universe is in accordance with God's design.
	If the evil in the universe is contrary to God's design, then God is not all powerful. If the evil in the universe is in accordance with God's design, then God is not all merciful.
	Either God is not all powerful or God is not all merciful.

        I might point out that in applications of this argument form, and other argument forms which depend upon a disjunction (an "or" statement) as one of the premises, a special case can occur in which the disjunction is between "p" and "it is not the case that p." Such a premise, because it is necessarily true, need not be stated (although it sometimes will be made explicit in order to make the pattern of argumentation clearer).

Simple Dilemma:

        "Simple dilemma" is the name I give to a special case of constructive dilemma when "r" and "s" name the same proposition (here represented by "r.").

	Either p or q.
	If p, then r.
	If q, then r.
	r.
	Example:
	Either God is not all powerful or God is not all merciful.
	If God is not all powerful, then God, as described by theologians, does not exist.
	If God is not all merciful, then God, as described by theologians, does not exist.
	God, as described by theologians, does not exist.

        Simple dilemma differs from constructive dilemma in that the latter, unlike the former, always has a disjunction (an "or" statement, remember) as its conclusion. For this example I have used the disjunctive conclusion of the previous argument to serve as a premise of this argument. This is an illustration of how these argument forms can be chained together to yield a more complex argument. Once again, all that is being claimed here is that if all the premises are true in each argument, the conclusion must also be true.

        (For another example of an argument in the form simple dilemma see "Identifying and Formulating Arguments.")

Categorical Syllogism Barbara:

        This next form of argument is probably one everyone is familiar with.

	All As are Bs.
	All Bs are Cs.
	All As are Cs.
	Example:
	All human beings are things made of matter.
	All things made of matter are things which ultimately disintegrate.
	All human beings are things which ultimately disintegrate.

        This form of argumentation was explored in depth by Aristotle. It is called a syllogism because, like some of our previous argument forms, it has two premises and a conclusion. It is called a categorical syllogism because each statement in the argument is what philosophy (and traditional logicians) call a "categorical" statement. There are four kinds of categorical statement, named with the vowels "A," "E," "I," and "O." The letters name the following statement forms:

A:	All S are P.
E:	No S are P.
I:	Some S are P.
O:	Some S are not P.

        Aristotle and his followers formulated rules for determining the validity of syllogisms built from these categorical statements. Incidentally, each valid argument was given a name (to make it easier to remember). This one was called "Barbara," in part because the three vowels in "Barbara" indicate that the syllogism is built from three "A" propositions.

Categorical Specification:

	Every A is a B.
	c is an A.
	c is a B.
	Example:
	Every action is a determined event.
	My thinking that every action is a determined event is (itself) an action.
	My thinking that every action is a determined event is (itself) a determined event.

        The name for this argument form I invented, but it is a common and important move in arguments. Often universal claims are made, claims which say that everything thing of a particular sort has such and such characteristics. A frequent and often essential move in an argument, then, is to bring these universal claims to bear on specific instances, which is what this argument form allows for.

Universal Instantiation:

	For every x, ... x ___.
	... a ___.
	Example:
	For every x, if x is a case of murder, then x is morally wrong.
	If aborting a human fetus is a case of murder, then aborting a human fetus is morally wrong.

        Here "... a ___" indicates any statement which some term "a" occurs. In this case "For every x, ... x ___" stands for a statement which is the same as "... a ___" except that wherever the term "a" appears in "... a ___," it is replaced by "x" (a variable) and "For every x" is prefixed to the entire statement. As you can see, "a" may occur more than once in the statement. The letter "a" need not stand for a single word, but it should abbreviate some noun phrase. In the example here it stands for "aborting a human fetus." The statement "... x ___" may be any kind of statement. It may, for example be a disjunction. In the example given it is a conditional statement. Notice, then, that the conclusion of this argument could serve as the premise of some other argument. This argument form, when it involves a conditional statement, as in this case, and coupled with (i.e., followed by an application of) modus ponens essentially amounts to what I have called "Categorical specification." But universal instantiation can be used in other contexts as well.

        While these are a mere sampling of the arguments forms that you might encounter in your exploration of arguments, combination of these is enough to get you started both on constructing lines of argumentation of your own and on analyzing the arguments of others.