It is often remarked that Indian logic (IL) has no conception of necessity. But what kind of necessity is absent in this system? Logical necessity is presumably absent: the structure of the logical argument in IL is often given as a reason for this claim. However even a cursory understanding of IL illustrates an abiding attempt to formulate the idea of necessity. In Dharmakīrti's classification of inferences, one can detect the formal process of entailment in the inferences arising from class inclusion. In Western philosophy, Leibniz's invocation of 'contingent necessity' as distinguished from the 'necessary necessity' is part of a tradition that finds value in the idea of contingent necessity. In contemporary philosophy, this has been championed by Armstrong, specifically in the context of understanding the necessity inherent in scientific laws. In IL, the analysis of 'invariable concomitance' (vyāpti) is of crucial importance and its definitions are very complex. This paper argues how vyāpti can be understood in terms of contingent necessity and also how the complex definitions can be interpreted as an attempt to define contingent necessity in terms of 'logical' necessity.