Morning Worship, October 14, 2012
Text: Luke 20:27-40
Title: Hypothetical Traps
Sermon Outline
I. Can God create a stone He can’t lift?
A. Sadducee background
B. Sadducee bluster
II. Can God create a bond He can’t break?
A. Marriage in this world
B. Marriage in the next world
III. Can God create a covenant He can’t dissolve?
A. Listening to the bush
B. Answering with a hush
Correction
In this sermon, I use a syllogism about cats and dogs. Unfortunately, I make some incorrect assertions about logic, soundness, and fallacy. The point of the illustration was to present the manner in which some misuse logic to their own ends. Logic is a useful tool. Used properly, it can invalidate unsound propositions and craft helpful and persuasive arguments. However, while logic functions as a tool to discover truth, it also can function to perpetuate falsehood. “Sound” arguments only include those whose premises are true. The tools of logic can be used with false premises as well as true. While “logic” may not appropriately be applied to such unsound conclusions (since some limit “logic” to “sound” arguments), the distinction is not immediately apparent or universally accepted. Thus a “logical” argument may be based on falsehoods.
When I said that an argument may be “sound but fallacious,” I used the terms incorrectly. I should have said that an argument may be valid but unsound. A syllogism that does not violate any of the rule of logic (that is, it is not fallacious), is deemed valid. It is deemed sound only if it is valid and all the premises are true.
Even worse, the example I used included a well-known fallacy, the undistributed middle. A better, yet imperfect illustration would have been the following:
First premise: “All cats are felines.”
Second premise: “Socrates was a cat.”
Conclusion: “Therefore, Socrates was a feline.”
While the first premise is true, the second is not. Thus the conclusion fails. This is an unsound but valid argument.
In the case of the Sadducees, their question has the ring of logic to it, but the unstated premise that marriage laws operate independent of the context was not true. Thus, their question, though facially logical, arose on unsound premises.
I regret this confusion especially as the sermon deals with some important issues from which my mistake ought not detract. My deepest apologies for this error.
Categories: Luke