Genomic sequencing has provided insight into the genetic characterization of many organisms, and we are now seeing sequencing technologies turned towards phenotypic characterization of cells, tissues, and whole organisms. In particular, single-cell transcriptomic techniques are revolutionizing certain aspects of cell biology and enabling fundamental discoveries about cellular diversity, cell state, and cell type identity. I argue here that much of this progress depends on abstracting one's view of the cell to regard it as a 'bag of RNA'.It may seem ridiculously naïve to characterize something with the complexity and intricacy of a cell as a 'bag of RNA'. I will argue that in fact it is a powerful and productive abstraction that is helping revolutionize our understanding of cell biology. The inspiration for this view comes from the field of biochemistry, which used a similar abstraction ('the cell is a bag of enzymes') to motivate an experimental program that led to many important discoveries about how the cell works [1,2]. It is of course manifestly incorrect to assert that the cell is a bag of enzymes, because indeed even bacterial cells depend on various structures, organelles, and other highly stereotyped forms of protein localization to accomplish the basic processes of life [3,4]. However, the idea of purifying enzymes and studying their activity in test tubes provided enormous insight into what was happening in the cellincluding metabolism, transcription, translation, and replication [5]. It is not clear that those discoveries would have been possible if one insisted on only studying intact cells in all their complexity.