1. Introduction

In contract law, the concepts of impossibility and impracticability relate to situations where a party cannot perform their contractual obligations. Both can provide grounds for excusing performance, but they differ in scope and application.

• Impossibility: Performance cannot be done by anyone; it is objectively impossible. It excuses contractual obligations automatically.
• Impracticability: Performance is not impossible but would cause extreme and unreasonable difficulty, expense, or hardship. It is a more flexible, subjective standard.

2. Impossibility of Performance

Definition:
Impossibility occurs when contractual duties cannot be performed due to unforeseen events beyond the control of the parties. The standard is objective.

Key Elements:

1. An unforeseen event occurred after contract formation.
2. The event made performance literally impossible.
3. The non-occurrence of the event was a basic assumption of the contract.

Examples:

• Destruction of the subject matter (e.g., building burned down).
• Death or incapacity of a person whose skills are uniquely required.

Key Case Laws:

1. Taylor v. Caldwell (1863) 3 B & S 826
   • A music hall burned down before concerts could occur.
   • Court held that the contract was discharged due to impossibility because the subject matter no longer existed.
2. Krell v. Henry (1903) 2 KB 740
   • Contract for renting a room to view the King’s coronation procession; the procession was canceled.
   • Held excusable due to frustration of purpose (related to impossibility in effect).
3. Codelfa Construction Pty Ltd v. State Rail Authority (1982) 149 CLR 337
   • Roadworks could not proceed due to a court injunction unforeseen at the time of contract.
   • Performance excused under frustration principles.

3. Impracticability of Performance

Definition:
Impracticability arises when performance is still possible, but extreme difficulty or expense makes it unreasonable to enforce. This is often called “commercial impracticability” in the U.S.

Key Elements (Restatement of Contracts):

1. An unforeseen event occurred.
2. The event makes performance extremely difficult or expensive.
3. The risk was not assumed by the party seeking excuse.

Examples:

• Sudden scarcity of essential materials.
• Dramatic increase in cost due to unforeseen circumstances.

Key Case Laws:

1. Transatlantic Financing Corp v. United States (1966) 363 F.2d 312
   • A shipping contract became commercially impracticable due to a sudden shortage of fuel.
   • Court excused performance due to extreme cost.
2. Mineral Park Land Co. v. Howard (1916) 172 Cal. 289
   • Mining operations rendered impracticable due to floods.
   • Performance excused; not strictly impossible but commercially impracticable.
3. Eastern Air Lines, Inc. v. Gulf Oil Corp. (1975) 415 F. Supp. 72
   • Fuel price increases due to an oil embargo rendered airline operations impracticable.
   • Court allowed defense based on commercial impracticability.

4. Key Differences Between Impossibility and Impracticability

5. Practical Implications

• Parties cannot rely on mere inconvenience or increased cost. Courts require substantial evidence.
• Force majeure clauses may incorporate both impossibility and impracticability.
• Impracticability often arises in modern contracts affected by inflation, supply chain disruptions, or geopolitical events.

6. Conclusion

• Impossibility excuses performance where it is objectively unfeasible.
• Impracticability excuses performance where it is feasible but extraordinarily burdensome.
• Case law illustrates that courts carefully examine the foreseeability, basic assumptions, and actual hardship before excusing performance.

✅ Summary of Six Key Case Laws

1. Taylor v. Caldwell (1863) – Destruction of subject matter (impossibility).
2. Krell v. Henry (1903) – Frustration of purpose due to cancellation (impossibility).
3. Codelfa Construction Pty Ltd v. State Rail Authority (1982) – Injunction prevented performance (impossibility/frustration).
4. Transatlantic Financing Corp v. United States (1966) – Extreme cost of performance (impracticability).
5. Mineral Park Land Co. v. Howard (1916) – Flood made mining operations impracticable.
6. Eastern Air Lines, Inc. v. Gulf Oil Corp. (1975) – Oil embargo made contract impracticable.