To the intriguing similarities that have been observed between Greek and Indian thought around the middle of the first millennium I will here add another: the interiorisation of ritual (specifically, the cosmic rite of passage), a process connected to the advent both of monism and of the all-importance of the inner self. The interiorisation of ritual is an idea that has been used by Indologists but not, so far as I know, by Hellenists. This is not to deny that there are differences between the two cultures in the way that the ritual is interiorised, and in the nature of the sources. But this chapter focuses on the basic similarity, and indicates a way of explaining why interiorisation occurred. I should add that, of the three kinds of explanation (listed in the Introduction) for the early similarities between Greek and Indian ‘philosophical’ thought, I favour – for the period before Alexander crossed the Indus – autonomous parallel development. Pre-Socratic and Upaniṣadic thought both exhibit coherent internal development, influenced in my view by the monetisation that made Greece and India (and China) different in this period from other societies. This is an argument that I will pursue in detail in a monograph. But the importance of monetisation will emerge even from within the relatively narrow confines of this chapter.

The interiorisation of Vedic sacrifice

Early Vedic sacrifice is based on a large series of imagined equivalences (or correspondences, or identifications) through which, especially in the Brāhmaṇas, what is within one's control (especially ritual control) corresponds with what is outside it. Ritual correspondence is defined by Clemens Cavallin as ‘a relation between two or more entities, which connects them in a way that makes it possible to influence one of them through the ritual manipulation of the other (or to explain e.g. the use of one entity in terms of the other)’. Such equivalences allowed sacrifice to be used as a means of encapsulating – so as to acquire or control – a wide range of phenomena.

However, this system of correspondences was not static. For the period of the Brāhmaṇas and early Upaniṣads the system of correspondences was transformed into monism, in a way that involved the individualisation and interiorisation of the sacrifice. I will describe how several scholars come to this view from different perspectives, so that my argument does not depend on the reliability of any one of them.