1. A ticket is all that is required for entry into the festival.
This is a potentially confusing example, because the word “required” is actually synonymous with “necessary,” which might lead one to conclude that the ticket is the necessary condition. However, if a ticket is all you need to get into the festival, then that ticket is sufficient for entry:
Sufficient → Necessary
Ticket → Festival
2. If you have the necessities, then that should be sufficient.
The sufficient and necessary conditions in this example are preceded by the classic indicator words “if” and “then,” respectively, reflecting the fact that “what is necessary” is the sufficient condition in this case, and of course “sufficient” is the necessary condition, leading to the following (potentially counter-intuitive) diagram:
Sufficient → Necessary
Necessities → Sufficient
3. We will leave if and when we are ready.
“If and when” is a strange but common colloquial phrase; from a conditional reasoning perspective, “if” and “when” both generally introduce sufficient conditions, so this seems somewhat redundant. What this sentence is really meant to express is that it is unclear whether an eventual state of readiness is a possibility (“if we are ready”) or a certainty (“when we are ready”), so technically, the phrase should be “if or when.” Although you will almost certainly not see this type of imprecise colloquialism on the LSAT, it would logically be diagrammed as follows:
Sufficient → Necessary
Ready → Leave
4. Your entry will be the only prize winner if, but only if, it is the only entry.
“If but only if” is a phrase that sometimes confuses students, but functionally it is no different from the phrase “if and only if.” Either way, the sentence expresses two ideas: the entry will be the only prize winner if it is the only entry (only entry → only winner), and the entry will be the only prize winner only if it is the only entry (only winner → only entry). Together, these lead to the following diagram:
only winner ↔ only entry
5. I’ll use the word “then” only if I use the word “if.”
Here, the classic conditional indicator phrase is “only if,” which generally (and in this case) introduces the necessary condition, meaning that in this unusual example, “if” is the necessary condition:
Sufficient → Necessary
Then → If
So, how did you do? Still have questions on these strange examples? Post them below!