ABSTRACT
Most issues concerning the vitiation of contractual consent arise in a context where the contracting party whose consent has been undermined is in other respects physically capable of granting or withholding his or her consent; instead, the consent is vitiated by overpowering force or influence or erroneous information. That consent must be given rationally and voluntarily. 1 However, there are occasions where the very ability to give “ free ” and “ reasonably intelligent ” consent is itself undermined by the physical, mental or physiological condition of the contracting party. 2 This is distinct from misguided or flawed decisions made by a person capable of making such decisions. The power or ability of a person to consent is distinct from the exercise of such power or ability. 3 The physical ability to provide consent to a contract may be said to be an obvious requirement; contracts by their nature represent the exercise of a freedom to submit oneself to an obligation to which, in the absence of one’s consent, the contracting party would not be subject. Moreover, in circumstances where a party is physically in a position to consent, the law can then presume that that party knows and understands the terms of the contract to which he or she has consented. 4 Where, however, that physical ability to give one’s consent is lacking, so too the requirements for a valid contract may be lacking. In Gibbons v Wright , 5 the High Court of Australia said that “ a contract requires the assent of both parties; a person of unsound mind is incapable of assenting; therefore no contract can come into existence between parties of whom one is of unsound mind ”. In Newry and Enniskillen Railway Co v Coombe , 6 a case concerned with an infant’s
1 Manches v Trimborn (1946) 115 LJKB 305, 305-307 (Hallett, J ); Moss v Moss [1897] 1 P 263, 268-269 (Sir FH Jeune, P).
