Buddhism has been seen, at least since the Theravāda reform movements of the late nineteenth and early twentieth centuries, as particularly compatible with Western science. The recent explosion of Mindfulness therapies have strengthened this perception. However, the 'Buddhism' which is being brought into relation with science in the context of the Mindfulness movement has already undergone extensive rewriting under modernist influences, and many of the more critical aspects of Buddhist thought and practice are dismissed or ignored. The Mind and Life Institute encounters, under the patronage of His Holiness the Dalai Lama, present a different kind of dialogue, in which a Tibetan Buddhism which is only beginning to undergo modernist rewriting confronts Western scientists and scholars on more equal terms. However, is the highly sophisticated but radically other world of Tantric thought really compatible with contemporary science? In this article I look at problem areas within the dialogue, and suggest that genuine progress is most likely to come if we recognise the differences between Buddhist thought and contemporary science, and take them as an opportunity to rethink scientific assumptions.