Pennywit v. Eaton was a United States Supreme Court case that dealt with the issue of whether a contract between two parties was valid. The case involved a contract between the plaintiff, Pennywit, and the defendant, Eaton, for the sale of a tract of land. The contract stated that the land was to be sold for a certain amount of money, and that the payment was to be made in installments. The Supreme Court held that the contract was valid and enforceable. The Court found that the contract was not void for lack of consideration, as the consideration was the promise of payment in installments. The Court also found that the contract was not void for lack of mutuality of obligation, as the parties had agreed to the terms of the contract and had both received something of value. The Court also held that the contract was not void for lack of capacity, as both parties had the legal capacity to enter into the contract. The Court also found that the contract was not void for lack of formality, as the parties had agreed to the terms of the contract in writing. The Court concluded that the contract was valid and enforceable, and that the plaintiff was entitled to recover the amount due under the contract.

In the case of Pennywit v. Eaton, the Supreme Court was tasked with determining whether a contract between two parties could be enforced when it had been made without consideration and in violation of an existing statute. The majority opinion held that such contracts were unenforceable, but Justice Field dissented from this ruling. He argued that while there may have been no consideration for the agreement at hand, courts should still enforce it if both parties intended to be bound by its terms and conditions. Furthermore, he reasoned that since statutes are not retroactive unless explicitly stated otherwise, any breach of law would not render a contract invalid as long as all other requirements for enforcement were met. In conclusion, Justice Field believed that even though this particular contract did not meet certain legal standards due to lack of consideration or statutory violations at the time it was created; those factors alone should not prevent its enforcement if all other necessary elements were present.