Syllogisms are one of the most recognisable question types in UCAT Decision Making. They can look intimidating because the language feels formal, but the core idea is simple.
You are given statements about groups and asked what must follow from them.
For example:
All surgeons are doctors.
Some doctors are researchers.
The important thing is to be precise about what those statements do and do not prove.
“All surgeons are doctors” means every surgeon belongs inside the larger group of doctors.
It does not mean every doctor is a surgeon.
“Some doctors are researchers” means there is at least one overlap between doctors and researchers.
It does not tell you that all doctors are researchers.
Words such as all, some, none and some are not matter enormously.
A simple Venn diagram can make these statements much easier to understand. If all A are B, you can draw A inside B. If no A are B, keep the circles separate. If some A are B, show an overlap.
One of the biggest mistakes is reversing statements.
If all cardiologists are doctors, you cannot conclude that all doctors are cardiologists.
Another mistake is creating relationships that were never given. If all surgeons are doctors and all dentists are doctors, that does not automatically tell you anything about the relationship between surgeons and dentists.
The safest rule is this: only conclude what must be true.
If a conclusion is merely possible, that is not enough.
Syllogisms become much easier once you stop treating them like complicated English and start treating them like diagrams of groups.
Practise translating the words into shapes. That usually makes the logic much clearer.
