Idaho Code § 29-103 : — CONTRACTSGENERAL PROVISIONS RELATING TO CONTRACTS —103 - PRESUMPTION OF CONSIDERATION TEXT PDF A written instrument is presumptive evidence of a consideration. Idaho Code § 29-103 [(29-103) R.S., sec. 3222; reen. R.C. & C.L., sec. 3314; C.S., sec. 5663; I.C.A., sec. 28-103.]