Neurologists have coined the word "aphantasia" to describe the condition of being unable to form visual mental images, publishing a study (nonpaywalled draft) of individuals with congenital aphantasia after first encountering a subject who described a sudden onset of the condition after an unrelated medical procedure. But how reliable is self-reported introspective data anyway?
We are because of others. We are born into this world with minds as naked as our bodies and we have to rely on others to feed, clothe us, and to teach us to think of ourselves as selves. The key is language -- grammatical speech and human culture build upon the brain's biological capacities to create a mind that is something different again than that with which we are born. We are conscious because we can speak to others and ourselves, because we can speak of ourselves to others and ourselves. Language gives us as individuals, memory, and as groups, culture, the social memory. Or so thought Lev Semyonovich Vygotsky, among others. Welcome to the the neuronaut's guide to the science of consciousness.