[17] Whenever parties make a contract it is possible that they have conducted themselves in such a way that it can be said by implication that they have agreed to rescind their bargain: Tallerman & Co Pty Ltd v Nathan's Merchandise (Victoria) Pty Ltd [1957] HCA 10; (1957) 98 CLR 93, 114; Commissioner of Taxation of the Commonwealth of Australia v Sara Lee Household & Body Care (Australia) Pty Ltd [2000] HCA 35; (2000) 201 CLR 520, 534. This was dealt with by Isaacs J in Summers v Commonwealth [1918] HCA 33; (1918) 25 CLR 144. In that case the parties had entered into a contract for the supply of a specified number of blocks of marble each of a certain dimension. For some time neither party took any step to perform the contract. It was held that the parties had abandoned or abrogated the contract. Isaacs J said (at 151-152):
"Whatever the terms of contract may be, it is possible for the parties so to conduct themselves as mutually to abandon or abrogate it. A position not too altogether dissimilar arose in the case of De Soysa v De Pless Pol [1912] AC 194. There, neither party had repudiated or refused to perform the contract, nothing in the nature of recision had occurred, but, said Lord Atkinson for the Privy Council: - 'One party to a contract is not bound to give the other unlimited time after a day named to do that which the other has contracted to do. There must be some point of time at which delay or neglect amounts to refusal ... In truth, the project seems to have been, to a great extent, if not altogether, abandoned by all the parties concerned.' In my opinion, that is the legal position here. Informally, but effectively, the parties have so acted in relation to each other as to abandon or abrogate the contract."
Summers v Commonwealth has been applied by the High Court in D T R Nominees Pty Ltd v Mona Homes Pty Ltd [1978] HCA 12; (1978) 138 CLR 423. This case concerned a contract for the sale of land. The purchaser purported to rescind the contract on the basis that the vendor had repudiated the contract by not complying with a condition. The vendor asserted that the purchaser's rescission constituted a wrongful repudiation and that the contract was thereby at an end. Stephen, Mason and Jacobs JJ (with whom Aickin J concurred) said (at 434):
"[T]here can be no doubt that ... when these proceedings were commenced, neither party, whatever may have been their reasons, regarded the contract as still being on foot. Neither party intended that the contract should be further performed. In these circumstances the parties must be regarded as having so conducted themselves as to abandon or abrogate the contract."
[18] In my view, the authorities to which I have referred establish not only that an agreement can be abandoned by conduct, but also that the question whether an agreement has been abandoned does not require one to examine whether the parties actually had the intention of abandoning the agreement; only whether their conduct, when objectively viewed, manifests that intention. This conclusion accords with the objectivist theory of contract which is now irrevocably entrenched in our law: Taylor v Johnson [1983] HCA 5; (1983) 151 CLR 422. See also Air Great Lakes Pty Ltd v K S Easter (Holdings) Pty Ltd (1985) 2 NSWLR 309, where McHugh JA (as his Honour then was) said (at 336) that "[t]he weight of authority in favour of the objective theory is too great".