I guess ideally we would have spent some time learning about the Buddhist perspective on how the mind works before tackling emptiness. What does it mean to say that phenomenon are merely imputed by thought? In order to really understand this, we have to examine the nuts and bolts of how we cognize the world around us.
Anyway, it’s never too late. So, for the students who completed Wisdom of Emptiness (Discovering Buddhism, module 14), you might want to check out the FPMT Basic Program module: Mind and Cognition (the way the mind knows phenomena and the mental factors that constitute the basis of our daily experience) available as a home study module from the FPMT store.
I found a commentary by Geshe Losang Jamphel on Mind and Cognition given in 2009 at Nalanda monastery online (PDF).. It’s a good introduction to Purbochok’s “Explanation of the Presentation of Objects and Object Possessors as Well as Awareness and Knowers”, one of the core writings on the topic. Emily Hsu’s terrific teachings on Mind and Mental Factors are available online as well on archive.org. Finally, an English translation of a short text by Akya Yong dzin Yang chan ga wai lo dro, “A Compendium of Ways of Knowing” was published by the Library of Tibetan Works and Archives (available from Amazon.com). The back cover reads “a short text used to train novice monks in the Gelugpa tradition”. It includes an accessible commentary by Geshe Ngawan Dhargyey.
This is a a huge, critical topic, so there lots of publications — Ven Lati Rinpoche’s “Mind in Tibetan Buddhism” is a classic. I’ve only listed a few online resources to get you started. After you’ve had a chance to do some reading about the Buddhist theory of mind, go back and re-examine emptiness, and you’ll see it with a new perspective.