Stem Cells and the Temporal Boundaries of Development: Toward a Species-Dependent View

Abstract

International audienceThe tacit standard view that development ends once reproductive capacity is acquired (reproductive boundary, or "RB," thesis) has recently been challenged by biologists and philosophers of biology arguing that development continues until death (death boundary, or "DB," thesis). The relevance of these two theses is difficult to assess because the fact that there is no precise definition of development makes the determination of its temporal boundaries problematic. Taking into account this difficulty, this article tries to develop a new species-dependent perspective on temporal boundaries of development. This species-dependent account stands against both RB and DB theses since neither of them reflects the differences between species in the temporality of their development. In this perspective, I propose to use stem cells as a tool to analyze (1) the different developmental capacities of an organism during its life; and (2) the different developmental temporal capacities between species. In particular, I will show that stem cells enable four distinct temporal developmental patterns to be distinguished, i.e., four distinct temporal boundaries of development in the living. I show how these four patterns can be interpreted differently depending on the perspective one has on the definition of development

Philosophy of Stem Cell Biology – an Introduction

“…So, like the natural kinds account, Leychkis et al's theoretical approach does not offer much guidance or clarification of ongoing stem cell research. Elaborating the 'state vs. entity' framework, Laplane (2013) distinguishes four ontological theories of stem cells: the entity, capability, system, and state views. The capability account is a functional counterpart of the entity theory, while the system account emphasizes cell environments as crucial for stemness.…”

“…The extent to which CSC theory is confirmed is a subject of intense scientific debate, with obvious clinical ramifications. 7 Laplane (2013) shows that dispute over the nature of stem cells is reprised in the CSC debate, and articulates the different clinical implications of entity, capability, system, and state theories. She then extends this pluralistic approach back into history, tracing the multiple strands of biological thought that contribute to CSC theory, as well as resultant ambiguities that complicate current scientific debate (ms.).…”

“…But none has yet been proposed. Laplane () offers a more fine‐grained classification of stem cells based on extent of potency. However, this account takes the distinction between pluri‐ and multipotent stem cells for granted rather than grounding it in theories of natural kinds.…”

Defining the Boundaries of Development with Plasticity

“…In a paper from 2003, Salazar-Ciudad et al show that cell differentiation may equilibrate faster than cell movement (see Laplane 2011). Molecular and physical interaction effects may not have the same consequence whether physical equilibrium is reached or not.…”

Explanation in Biology

“…For recent exceptions seeFagan (2013),Laplane (2011), andLeychkis et al (2009).3 A complementary view is offered byGross (2015, this volume) who defends the explanatory value of non-dependence relationships.…”