Galton, reversion and the quincunx: The rise of statistical explanation.

Over the last six decades there has been a consistent trend in the philosophy literature to emphasize the role of causes in scientific explanation. The emphasis on causes even pervades discussions of non-causal explanations. For example, the concern of a recent paper by Marc Lange (2013b) is whether purported cases of statistical explanation are "really statistical" or really causal. Likewise, Michael Strevens (2011) argues that the main task of statistical idealizations is to distinguish between the causal factors that make a difference to the phenomenon to be explained and those that do not. But, the philosophy literature poorly reflects the history of the development of statistical explanation in the sciences. Francis Galton's (19th century) explanation for the laws of heredity is our case. Galton's statistical explanation was both innovative for his time and influential to our contemporary sciences. The key points to understanding Galton's statistical explanation for reversion is that it is autonomous from the real-world biological properties that make up an instance of reversion while still being approximately true of many real-world biological phenomena. Ours is an expanded discussion of ideas originated in Hacking (1990) and Sober (1980). We will articulate these features and compare our account with that of Lange and Strevens.

Baroreflex control of sympathetic nerve activity in hypertensive pregnant rats with reduced uterine perfusion.

OBJECTIVE: Baroreflex sensitivity is reduced in women with preeclampsia. The aim of this study was to determine whether baroreflex control of renal sympathetic nerve activity (RSNA) is altered in pregnant rats with reduced uterine perfusion (a model of human preeclampsia). METHODS: Uterine perfusion was reduced in the third trimester by clipping the distal aorta and uterine branches of the ovarian arteries. RSNA baroreflex parameters were compared at term gestation in rats with reduced uterine perfusion (n = 12), in normal pregnant rats (n = 14) and in nonpregnant rats (n = 14). RESULTS: Reduced perfusion rats were hypertensive (123.6 +/- 2.3 mm Hg), and normal pregnant rats were hypotensive (97.7 +/- 2.2 mm Hg), compared with controls. In rats with reduced perfusion, the baroreflex was shifted to a higher set-point, and maximum and minimum RSNA were increased compared with normal pregnant rats. CONCLUSION: The blunted baroreflex gain of normal pregnancy is maintained in rats with reduced uterine perfusion, but a hypertensive shift in baroreflex function exists in this rat model that is associated with a reversal of the reflex maximum and minimum RSNA observed in normal pregnancy.