Constructing Arguments

Classical Argumentation and Basic Logic

Bioethics, like the philosophical tradition more generally, relies heavily on formally constructed arguments to accomplish its aims. Moral rightness and wrongness are not empirically observable phenomena, and so assertions about the existence or nature of these concepts require argumentation. Gregory Johnson defines a formal argument as “a set of statements, one or more of which are intended to support another in the set. The statements providing support are the premises, and the statement receiving support is the conclusion,” (Johnson, 2016). Most arguments also contain some set of implicit assumptions which undergird the argument.

To summarize:

Conclusion: The idea or statement the author wants you to agree with/believe/accept as true and convincing. The ultimate purpose of any argument is demonstrating the truth of this claim.

Premises: The evidence given to support the conclusion. These statements can be either true or false.

Assumptions (aka “Suppressed” or “Hidden” Premises): Unstated, additional presuppositions or pieces of evidence that must be true in order for the premises to support the conclusion. They connect the premises and conclusion together.

Accordingly, we get three opportunities to dissent from a given argument. We can challenge one or more of the premises, we can challenge the claim that the premises and the assumptions prove or adequately support the conclusion, or we can challenge the assumptions.

There are two routes for challenging one of these components of an argument: validity and soundness.

Finally, it is worth mentioning briefly that not all arguments will be deductive in nature. Whereas deductive logic is entirely self-contained and can generate universal claims (I.e., “all bachelors are men”), inductive logic involves “extrapolating from observed patterns to conclude that a given conclusion is probably true” (Gensler, 2010). We can thus differentiate between arguments which are deductively valid vs. those which are inductively strong, where the latter refers to arguments which “are not deductively valid, and for which, if the premises are true, then they make it probable that the conclusion is true” (Johnson, 2016). Consider the following comparison to illustrate:

Deductively Valid                                                Inductively Strong

P1. All who live in Utah live in the U.S.                P1. Most who live in Iowa were born in Utah

P2. Mitch lives in Utah                                           P2. Mitch lives in Iowa

C. Therefore, Mitch lives in the U.S.                     C. Therefore, Mitch was probably born in Utah.

Bioethics Arguments

Some authors opt to offer their arguments explicitly in numbered premise-conclusion format, and this clarifies precisely what the author believes they are arguing for and allows readers to analyze the argumentative structure on the author’s terms. Take a contemporary example from bioethicist and philosopher Jessica Flanigan against car seat belt mandates:

“1. If a person’s autonomous choice is not harmful to others, then public officials should not paternalistically use force or threats of force to prevent him from making that choice.

2. Riding unbelted is an autonomous choice that is not harmful to others.

3. Therefore, public officials should not paternalistically prevent people from riding unbelted.” (Flanigan, 2017)

While some authors express their argument in this way, many do not, and so it becomes the reader’s responsibility to reformulate claims into standard argumentative form.

These two sentences convey an argument, but one that needs to be teased apart and cleaned up into premise-conclusion form before it can be properly analyzed.

Rewritten in standard argument form, the quote would read:

Premise 1: It is God and only God’s job to decide who is worthy to live and not. It is wrong for us to “play God” and decide for ourselves whose life is worthy and whose is not.

Premise 2: Abortion entails humans “playing God” and exercising their own discretion concerning whether some human life is less valuable or worthy to live.

Conclusion: Therefore, abortion is morally wrong.

This argument is logically valid. If it is wrong to play God, and if abortion entails playing God, then abortion is morally wrong. Is the argument sound, though? Is abortion really playing God? And what unstated assumptions are at play? (ex. that God exists and dictates morality). What about the next example?

This argument is also logically valid. If abortion reduces large negative impacts on society, and if reducing large negative impacts on society is sufficient for moral permissibility, then abortion is morally permissible. Is the argument sound, though? And what unstated assumptions are at play? (ex. That the only relevant or decisive consideration regarding the lives of millions of unwanted children is their societal impact).

It can be difficult to identify all the premises and unstated assumptions in a lengthy article or book, especially when the arguments are highly complex, involving many premises and sub-arguments.

Tips for Reading Bioethics Arguments

1. Decide exactly what the conclusion is and identify precisely what is being argued for.

2. Identify the premises (reasons) offered in support of the conclusion (noting that not everything discussed will be related to the conclusion).

3. Identify assumptions, stated and unstated.

4. Try to figure out what the structure of the argument is as much as possible-how are the reasons related to the conclusion, how are they related to each other?

5. Ask whether the premises are true.

6. Ask whether the premises really support the conclusion.

Works Cited

Flanigan, Jessica. “Seat Belt Mandates and Paternalism.” Journal of Moral Philosophy 14, no. 3 (June 22, 2017): 291–314. https://doi.org/10.1163/17455243-46810050.

Fogelin, Robert J., and Walter Sinnott-Armstrong. Understanding Arguments: An Introduction to Informal Logic. 7th ed. Australia; Belmont, CA: Thomson Wadsworth, 2005.

Gensler, Harry J. The A to Z of Logic. Lanham, Md.: Scarecrow Press, 2010.

Johnson, Gregory. Argument and Inference: An Introduction to Inductive Logic. Cambridge, Massachusetts: MIT Press, 2016.