princeton university professor and author of "from black lives matter to black liberation," keengaup yamahtta taylor. the numbers are on the screen. you can also contact our guest with text-message. include your name and city.yo the number is 202-838-6251. professor taylor, when you hear the term "all lives matter," what's your reaction? >> guest: well, i think that the problem with the phrase "all lives matter" is that in many ways it's an assumption that many of us begin with. the point of saying "black lives matter" is to really highlight the extent to which black lives have not mattered in the united states. most recently, concerning the issue with police abuse and violence.. and i think the reluctance to embrace that really shows the depth of the lack of understanding about what the conditions of african-americans in this country actually is, and to some extent i think we can understand that. we live in a deply segregated country where white peel have no idea what black people's livers are like in this country, and it's not the same necessarily for african-americans who see the lives of white p