 Perhaps the most confronting aspect of big data science as discussed in this entry is the extent to which it deviates from understandings of rationality grounded on individual agency and cognitive abilities (on which much of contemporary philosophy of science is predicated). The power of any one dataset to yield knowledge lies in the extent to which it can be linked with others: this is what lends high epistemic value to digital objects such as GPS locations or sequencing data, and what makes extensive data aggregation from a variety of sources into a highly effective surveillance tool. Data production and dissemination channels such as social media, governmental databases and research repositories operate in a globalised, interlinked and distributed network, whose functioning requires a wide variety of skills and expertise. The distributed nature of decision-making involved in developing big data infrastructures and analytics makes it impossible for any one individual to retain oversight over the quality, scientific significance and potential social impact of the knowledge being produced.