Roots and options are two of the most basic references of social action. Roots are references that operate by backward linkages; options are references that operate by forward linkages. Social actions may be said to be root-oriented or option-oriented. The specificity of Western modernity resides in the equation between roots and options. Such an equation confers a dual character on modern thought: on the one hand, it is a thought about roots, on the other, a thought about options. The thought about roots concerns all that is profound, permanent, singular, and unique, all that provides reassurance and consistency; the thought about options concerns all that is variable, ephemeral, replaceable, and indeterminate from the viewpoint of roots. The two major differences between roots and options are scale and time. Roots are large-scale entities; options are small-scale entities. Because of this difference of scale, roots are unique while options are multiple.Roots and options are also distinguished according to time. Societies, like social interactions, are built upon a multiplicity of social times, and differ according to the specific combinations and hierarchies of social times that they privilege. Drawing freely on Gurvitch's (1969, p. 340) typology of social times, I want to understand roots in terms of a combination of a) long duration time and time au ralenti; b) cyclical time, the time that danse sur place; c) belated time (temps en retard sur lui meme), time whose unfolding keeps itself in wait. Options, on the other hand, are characterized by a combination of a) accelerated time (temps an avance sur lui meme), the time of contingency and discontinuity; b) explosive time, the time without past or present and only with future. In a continuum between glacial time and instantaneous time, modern roots tend to cluster around glacial time, while modern options tend to cluster around instantaneous time. If in roots the tempo tends to be slow, in options it tends to be fast. The root/option duality is a founding and constituting duality, that is to say, it is not subjected to the play it itself institutes between roots and options. In other words, one does not have the option not to think in terms of roots and options.In this equation of roots and options, modern society views medieval society and distinguishes itself from it. In medieval society the primacy