intended act.61 This sense of conditionality is based upon the rarely held belief that no obligations requiring a future performance can meaningfully be entered into. It is a position which therefore denies the obligatory force of most contracts. As a highly sceptical position, the sense of conditionality to which it gives rise is discounted here.

Given the various meanings of conditionality outlined above which are accepted, do any of these describe circumstances which would render a statement not to be a promise under the definition suggested earlier? That definition suggested that a promise is a statement by which a speaker places himself under a commitment as to a future act. Commitment denotes a present obligation (whether of a moral or legal nature). Given this definition, conditionality of the type mentioned in example three – the condition suspensive of the existence of an obligation – would prevent a statement from being a promise. If the nature of the statement as a binding obligation is postponed until some future contingent event, then unless and until such a contingency creates an obligatory effect, there can be no promise as there is no commitment. On the other hand, a condition which relates only to the performance of a firm commitment (example 2), or which is a resolutive condition (and thus relates to the possible future termination of an existing firm commitment), are types of condition which do not prevent a statement from being a promise.

It seems therefore that promises may be unconditional, or may be conditional in any sense other than suspensive of the obligation undertaken by the promisor. A speaker who is not yet bound to any commitment, and who may therefore withdraw from making any commitment until a stated event occurs, has not made a promise.

(c)  Unilaterality

Most people’s paradigm image of the promise is probably a unilateral act (though as will become clear in later chapters of this work, there is also a long tradition of conceiving of bilateral contract as an exchange of promises). It is useful then to begin by examining those promises which are unilateral. To do so, one must ask: what is meant by a promise being unilateral?

61A concern which is said to explain the absence of the phenomenon of promising from Tongan society, where the future is considered uncertain: see further discussion of this below, at p. 53.

As with gratuitousness and conditionality, the concept of unilaterality is one which can be utilised to analyse the whole spectrum of obligations, not simply the promise. To begin with, just as with the other two features we have been discussing, unilaterality has its opposite: bilaterality (or multilterality, in multi-party obligations). However, as with gratuitousness, there are conceivably a number of possible meanings of unilateral, which is where confusion may creep in. First, a unilateral obligation might mean one which is constituted by one party only, in other words, where it requires the actions or behaviour of only one party to give rise to the obligation. Alternatively, a unilateral obligation might be one where only one party assumes any duties or commitments under the obligation. In that sense, unilateral would be meant in a way synonymous to one of the meanings of gratuitous outlined earlier, that is an obligation undertaken without any ability to compel a counter-performance. These two distinct senses of the concept of unilaterality may be demonstrated by reference to the following examples:

I promise to pay £100 to my brother.

I promise to draft a will for my client for no consideration. My client accepts my promise.

In the first example, if we assume for the moment that a promise needs no acceptance on the part of the promisee before it can bind (an assumption which would not, in legal terms, hold good in every jurisdiction), then this promise might be unilateral either in the first sense outlined (because the promise may be constituted by the undertaking of the promisor alone, whether orally or in writing) or in the second sense (in that no duty or commitment is assumed by the promisee). On the other hand, in the second example, which essentially describes a contract lacking mutual consideration (again, this is not possible in all jurisdictions), the promise of the lawyer to draft a will for his client would be unilateral in the second sense (in that it imposes a duty on only one party, the lawyer) but not in the first: as a contract, it would require at least an indication of assent to the contract by the promisee, typically in the form of an acceptance, before the obligation could be constituted.62

In any legal system which requires mutual consideration before ­voluntaryobligationsmaybeconstituted,theideaofaunilateralobligation

62In the Louisiana Civil Code, a further possible sense of unilateral is stipulated, that being non-mutual: ‘[a] contract is unilateral when the party who accepts the obligation of the other does not assume a reciprocal obligation’ (CC Art. 1907). A synallagmatic, or mutual, contract arises ‘when the parties obligate themselves reciprocally, so that the obligation of each party is correlative to the obligation of the other’ (CC Art. 1908).

in either of the two senses of the term discussed above would be anathema: there could be no voluntary obligations constituted by only one party or which impose duties on only one party. However, even the Common law, with its doctrine of mutual consideration, allows unilateral voluntary obligations to be undertaken by deed.63 In jurisdictions where obligations may be constituted by the actions of one party alone, or where there is no requirement of mutual consideration, obligations might be unilateral in either sense. Which sense of the word a jurisdiction chooses to use is, of course, entirely a matter for it, though if the second sense of the term unilateral were to be chosen (the sense of an obligation which imposes a duty on only one of the parties) there would then be a somewhat unnecessary and perhaps confusing overlap with the meaning of gratuitous defined as an obligation in which one party cannot compel a counter-performance. There might therefore be thought to be good sense in choosing the first definition of unilateral rather than the second, as for instance the drafters of the Draft Common Frame of Reference (DCFR) have done,64 though such a course has not invariably been adopted by national jurisdictions.

The complications with understanding the idea of unilaterality do not end there. Some jurisdictions use the term unilateral both to refer to obligations constituted by only one party as well as to refer to obligations where only one party comes under any duties. The first usage describes what is called the nature of the juridical act, which is to be distinguished from the second sense, which describes the number of parties having duties under such an act. In such systems, while contract is always defined as a bilateral juridical act, two parties being required to constitute a ­contract, if mutual consideration is not a requirement of the law then contracts can be described (in the second sense of the term) as unilateral or bilateral, depending on whether one or two parties come under contractual duties. This can result in the confusing situation where a contract can be described as both bilateral and unilateral at the same time: bilateral because it is a bilateral juridical act, but unilateral in that it imposes duties on only one party. Such an analysis is, for instance, adopted in South African law.65 The same position prevails

63See later discussion of contracts in deed form at p. 166. The separate and unusual phenomenon of English Law’s ‘unilateral contract’ is ignored for the moment (for discussion, see Ch. 4, at p. 220).

64See DCFR Art. II.-1:101, II.-1:103. The DCFR restricts use of the term unilateral to undertakings (including promise) which are constituted by one party alone; there can therefore be no such thing as a unilateral contract in DCFR terms.

65See Van der Merwe et al., Contract, p. 9; see also p. 32, where it is explained that multilateral juristic acts are those ‘in which at least two persons must participate, in contrast with