Arguments in which one statement is left assumed are called enthymemes. Most logical arguments encountered in daily life are enthymemes. We can use the tools of logic to determine the assumption being made in an enthymeme.
Let’s examine three enthymemes in the Bible, all on the topic of Gospel salvation.
“Whoever has been born of God does not sin, for His seed remains in him” – 1 John 3:9
The first statement is the conclusion (it is followed by the premise indicator “for”). The “whoever” becomes all people, but the later “not” makes it negative, so a good translation would be “No person born of God is a person who sins.” To translate “His seed remains in him,” we must use one of the terms in the conclusion. The second “him” refers to the person born of God, so a good translation would be “All persons born of God are persons in whom God’s seed remains.” Since the conclusion is a universal negative and the premise is affirmative, the assumed premise must be a universal negative (otherwise the argument would be fallacious, and we assume that enthymemes represent valid syllogisms if possible). Also, the terms in the assumed premise must be the terms used once so far, namely “persons in whom God’s seed remains” and “persons who sin.” Thus the entire syllogism (with the assumed statement in parentheses) would be:
(No person in whom God’s seed remains is a person who sins.)
All persons born of God are persons in whom God’s seed remains.
Therefore, no person born of God is a person who sins.
“They have no root in themselves, and so endure only for a time.” – Mark 4:17
The “so” indicates the conclusion, that they endure only for a time. The context shows that they are the stony soil, the ones who stumble in times of persecution. We can call them stony soil, and translate the conclusion “No stony soil are those who endure.” The given premise would then be “No stony soil are those with roots in themselves.” The assumed premise must be universal (because the conclusion is universal),must be affirmative (since the other premise is negative), and must use the terms “those who endure” and “those with roots in themselves.” The premise must also distribute “those who endure” to avoid the illicit major. The valid syllogism under this enthymeme would be thus:
(All those who endure are those with roots in themselves.)
No stony soil are those with roots in themselves.
Therefore, no stony soil are those who endure.
“They received the word with all readiness, and searched the Scriptures daily to find out whether these things were so. Therefore many of them believed” – Acts 17:11-12
The conclusion is “Many of them believed,” the subject being the Berean Jews. These Berean Jews “received the word” readily and “searched the Scriptures.” The syllogism so far could be translated: “All Berean Jewss were ready word receivers, therefore some Berean Jews were new believers.” The middle term “ready word receivers” must be distributed, so the complete syllogism would be:
(All ready word receivers were new believers.)
All Berean Jews were ready word receivers.
Therefore, some Berean Jews were new believers.