Indeed, Brown may desire the shoes but he may not have gold or another commodity acceptable to Jones, but Jones, having confidence in Brown's future ability and willingness to provide acceptable commodities, may therefore be willing to transfer the shoes to Brown at once and trust him to transfer acceptable commodities later. The payment, in other words, is deferred. Since either man or both is likely to forget the exact nature and terms of this deferred payment, some written evidence is usually prepared to describe it. This written evidence may be simply a book entry, or it may be a special instrument drawn up to which Brown subscribes. In any case the credit precedes and exists independently of the instrument; contracts, written or parol (oral), characterize a credit economy and may well be regarded an essential attribute of credits, but emphasis on this feature is likely to becloud the more fundamental element - confidence.
Reduction of the credit contract to writing serves several purposes, but parol credit is just as thoroughly credit as is that evidenced by written instruments. Writing gives the contract legal definiteness; what was possibly vague, easily forgotten, and therefore subject to dispute, becomes definite and lasting. If left in the form of an entry in an open book account, it is still subject to dispute by the debtor, and the burden of proof of its validity and correctness rests upon the creditor. But if reduced to writing and signed by the debtor, the law presumes that it was then and is now valid and correct, hence the burden of proof to the contrary is upon the debtor. Writing also makes the contract more easily transferable. Writing, however, does not change its credit basis; the credit instrument cannot be better than the credit which it embodies; its safety and security do not lie in the form, but in the credit conditions underlying its creation; the promissory note by which a book account is closed has no greater security than the book account itself; it simply renders the account in a more convenient form for the creditor.
Jones, however, at the time he grants credit to Brown, may not know what specific commodities he may want at the maturity of the credit; it serves his convenience, therefore, to have Brown promise to pay in terms of the most commonly acceptable commodity in the community, which Jones believes he can exchange for things then wanted. It is, therefore, drawn in terms of money. Money is the standard of deferred payment. Credit is the deferred payment. The credit instrument is the certificate of such deferred payment. The four attributes of credit are, therefore, standard money, confidence, time, and contract.