Distance Contracts and Acceptance of the Offer
Problems can arise where there is a period of time between any offer and acceptance passing, during which one of the parties wishes to change their own position, for example, to withdraw an offer or an acceptance. Where communication is not instantaneous, such as by post, there have to be legal rules to cope with such problems. The so-called postal rule in the U.K. is that an unqualified acceptance which is posted concludes a bargain when it is posted. The bargain is not concluded when the post is received. The rationale for this appears to be that once posted the acceptance can not be intercepted, and that it might be a greater injustice to allow the offeror to withdraw an offer when the acceptor had done all he could to accept. A similar position applies in the USA under their ‘mailbox rule’, but the legal rule is by no means universally accepted and indeed it still courts controversy today. Other types of communication may be regarded as having the essential features of face-to-face communication, such as voice telephony or telex, in that communication is instantaneous英语论文网 【http://www.51lunwen.org】. In the case if instantatneous/face-to-face communications, the postal rule is not relevant and it is the communication and understanding of an intelligible acceptance that is critical. Other types of communication are of debatable legal status, such as facsimile, email or SMS text message on a mobile phone.

The generally accepted legal rule is that an offeror may stipulate how an offer is to be accepted, for example as to the manner and time of acceptance. This may override other rules such as the customary postal rule, by providing that acceptance is not constituted until an acceptance is received. Indeed there has been case law in England to the effect that competitive tenders that have been invited on an equal footing have all to be considered on an equal footing. This effectively means that an offeror may have rights to have his offer considered, if not actually accepted.

To summarise;
When is the contract formed?

A contract must constitute an offer and an acceptance between the parties. This offer and acceptance signifies that a meeting of the minds - consensus in idem – has been reached. If you alter the terms of your acceptance then there is no contract. What has happened is that the roles have been reversed and the acceptance becomes a qualified acceptance or counter offer which must be unconditionally accepted by the original offeror.  In the case of automated decision making, it appears that if the machine has no discretion, or the 本文来自：英语论文网 【http://www.51lunwen.org】