The Ideas of Ludwik Fleck and Their Application to the Eukaryotic Cell Cycle, the Restriction Point, and G1-phase Control Stephen Cooper Department of Microbiology and Immunology, University of Michigan Medical School Ann Arbor Michigan 48109-0620 e-mail:
[email protected] Abstract The ideas of Ludwik Fleck (1896-1961) analyzing the conservative nature of scientific ideas are discussed and applied to the proposed G1-phase restriction point as a regulatory element of the mammalian cell cycle. Fleck proposed that ideas become fixed and difficult to change because criticisms of current and dominant models are either ignored or turned to support of the current model. The idea of a thought-collective leading to the stability of ideas is a central theme of the ideas of Ludwik Fleck. 1 Evidence conforms to conceptions just as often as conceptions conform to evidence. Ludwik Fleck, 1935 Introduction The continuum model of eukaryotic cell-cycle control is now almost 25 years old (1,2). This alternative view was actually generated a number of years earlier based on studies of the bacterial cell cycle (3). Since its first proposal, the continuum model has not made much headway against what may be called the G1-phase control model of the cell cycle, a model that is current, dominant, and accepted by a broad consensus of researchers in the field of eukaryotic cell-cycle studies. It is important to understand how the G1-phase control model has remained so dominant despite the success of the alternative continuum model view of the cell cycle in explaining myriad published experimental results on the cell cycle.