Conditional Reasoning on the LSAT: Do You See It Everywhere?

Many students, upon being introduced to the foundational concepts of conditional reasoning and deductive logic, begin to “see” conditionality everywhere. In a sense, it is everywhere – especially in deductive reasoning, which forms the basis for most LSAT questions. You may even find comfort in the rule-driven environment of formal, or deductive, logic. There is nothing wrong with that, per se. But you need to know when you’ve gone far.

To Diagram or Not to Diagram?

It’s usually the clear relationships and the unusual conditional indicators (such as “only when,” “unless,” etc.) that should be diagrammed or seen in a purely conditional light. Similarly, if you see multiple conditional statements in the same argument or fact set, check to see if they share similar or identical conditions. If they do, you are probably being tested on your ability to form chain relationships (aka the “law of syllogism”).

But, not everything should be diagrammed, and not every “if” will turn a stimulus into a conditional reasoning problem! If you try to reduce everything into a black-and-white diagram, you stop seeing the subtleties of language that sometimes matter the most. The makers of the LSAT specifically try to muddy the water at times to make sure you really understand the argument in all of its complexity. I’ve seen smart students lose all common sense, turning virtually every argument into something resembling an electrical circuit diagram. This is counterproductive.

And while we’re on this topic, we don’t advocate using Venn diagrams to solve LSAT Logical Reasoning questions (see Venn Limits for our view of Venn on the LSAT). That said, Venn diagrams can be useful for explanatory purposes in certain situations.

Conditionality in Deductive Logic

To sum up, you must master conditionality in deductive logic. It is present (in some shape or form) in almost every LR question, along with many Linear and Grouping games. That said, don’t “overthink” conditional reasoning, or you’ll start missing the forest for the trees. Only about 15% of all LR questions will test your conditional reasoning skills directly. If you find yourself diagramming more than a handful of problems, chances are you’ve gone too far.