While trade and exchange rules have existed since antiquity, modern contractual laws have been traceable in the West since the Industrial Revolution (1750), when more and more people were working in factories for cash wages. In particular, the growing strength of the British economy and the adaptability and flexibility of the English common law have led to a rapid evolution of English contract law. The colonies within the British Empire (including the United States and the Dominions) would pass the law of the motherland. During the 20th century, the growth of export trade led countries to adopt international conventions such as the Hague-Visby rules and the Un Convention on International Goods Contracts to promote uniform rules. In certain circumstances, an unspoken contract may be established. A contract is implied when the circumstances imply that the parties have entered into an agreement when they have not expressly done so. For example, John Smith, a former lawyer, can implicitly enter into a contract by going to a doctor and being examined; If the patient refuses to pay after the examination, the patient has broken an implied contract. A contract implied by law is also called quasi-contract because it is not actually a contract; Rather, it is a means for the courts to remedy situations in which one party would be unfairly enriched if it were not obliged to compensate the other. The Quanten Meruit claims are an example. In some U.S. states, e-mail exchanges have become binding contracts. In 2016, the New York courts ruled that the principles of real estate contracts applied to both electronic communications and electronic signatures, provided that “their content and subscription meet all applicable status requirements” and in accordance with the Electronic Signatures and Records Act (ESRA).  TIP: If it is not possible to enter into a written contract, make sure you have other documents such as emails, quotes or notes to your discussions to help you identify what has been agreed.
The terms of a contract in Anglo-American law are that there be an offer, acceptance, consideration and intent to fulfill legal obligations. Scottish law does not require any consideration because of its civil origin. Contractual consent is generally discovered by an objective and non-subjective study of the parties` positions. The possibility that they did not actually agree on the same thing – consensus ad ditto – is dealt with under the Law on Errors or Errors.