As for the obligation to carry out the work, the more evident view is that the worker in a profit-sharing investment, sharecropping, or orchard-tending contract is negligent if he fails to perform the work required by the contract. Although the contract is revocable, as long as it remains in force it imposes two obligations: safeguarding the property, as with a deposit entrusted for safekeeping, and performing the work required by the contract.

This follows by analogy from the principles of our school, since we require either co-owner to participate in sales and repairs to the extent customarily needed by the other, such as repairing what has fallen into disrepair. This applies to co-ownership, and the same therefore applies to contractual partnerships, whose purpose is to conduct the agreed activities. Failing to act under profit-sharing investment, orchard-tending, and sharecropping contracts may cause greater harm than failing to repair a dilapidated property held in co-ownership, and than failing to sell a jointly owned asset or its use. In the latter cases, the co-owner can sell his share, whereas here the worker has misled him and deprived him of the benefit of his property.

If the contract is invalid, not all its usual consequences are established, such as the obligation to exchange possession and carry out the agreed activities, the permissibility of dealing with and benefiting from the property, and similar matters. Nevertheless, if possession is taken under it, this is possession authorized by a contract, and is therefore unlike a usurper’s taking possession without permission.

For this reason, the jurists said: Whatever entails liability upon taking possession under a valid contract also entails liability upon taking possession under an invalid contract, such as property sold or leased. Whatever does not entail liability upon taking possession under a valid contract likewise does not entail liability upon taking possession under an invalid contract, such as property held in trust under profit-sharing investment contracts, partnerships, and similar arrangements, because permission has been given. Hence the scholars disagreed over whether ownership is acquired by taking possession under such a contract, and over what one is entitled to