Glossary · Also called Dual aspect
Duality concept
Every transaction affects the accounts in two equal and opposite ways.
What it means
The principle underlying double entry that each transaction has two aspects, a debit and a credit of equal amount.
Example
Buying goods for cash increases inventory and decreases cash by the same amount.
Why it matters
It is why the accounting equation always balances and the basis of the whole double-entry system.
In practice
The duality concept is the basis of double entry. Each transaction produces one debit and one equal credit, so the accounting equation stays in balance and the trial balance totals agree.
Buy a delivery van for RM18,000 by cheque. The motor vehicles account is debited RM18,000 and the bank account is credited RM18,000. Two accounts move in opposite directions by the same amount. Because both effects are always recorded, total debits equal total credits at any moment. This is what makes a trial balance a useful arithmetic check.
Students sometimes muddle duality with the business entity concept. Duality is about how you record: every entry has two sides. The business entity concept is about whose transactions count: it keeps the owner's private affairs out of the firm's books. One describes how to record. The other decides what you may record at all.
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Related terms
Syllabus reference: Cambridge 0452 and 0985, syllabus for 2027 to 2029, sub-topic 7.1 Accounting concepts (page 19).
Definitions here are general accounting explanations for study. For your board's exact wording, see its official syllabus via Sources.
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