Changing challenges and paradigms.

Change comes as a surprise because things do not happen in a straight line. Concepts often evolve haphazardly, reacting to specific events. Assumptions are made but are not challenged, sometimes for political or social expedience. It has long been recognized that the dose makes the poison. Concepts of the relationship evolved from both events and the availability of exploratory tools. There are consequences to risk aversion. The general concept of hormesis is perhaps not unexpected. The acceptance of multiphasic dose-responses has the potential to unleash additional and productive insights into this relationship. The activities of BELLE and its Newsletter provide an excellent example of what can be achieved when dogmas are challenged by the accrual of information that has not been previously examined to see whether additional insights are possible. A forthcoming challenge will be the critical examination of all the inputs and assumptions that will be used in the increasing sophistication of biological modeling.