In November 2001 in Strasbourg, France, the Human Frontier Science Program and the European Science Foundation brought together leaders of research funding agencies from Europe, North America, and Japan to discuss major problems in our current approaches to promoting careers in the natural sciences, with a special emphasis on the life sciences. Central to our discussions were the challenges faced by postdoctoral fellows and the need to create a new paradigm for postdoctoral training that would be more expansive in its goals and better attuned to the needs of both society and young scientists. Leaders of funding agencies, which are the primary supporters of science in most countries, are in a unique position to facilitate changes in the culture of research training and support. Thus it was most gratifying that a general consensus was reached regarding key issues relevant to this policy forum: the problem of the growing number of postdoctoral researchers competing for a limited number of secure academic positions.
To begin with, our guiding principle was that the purpose of a postdoctoral fellowship is first and foremost to provide research apprenticeship and professional training. At the same time, we recognized that the traditional model of science education and training at academic research institutions is in many ways failing. This model, a legacy of the 19th century, has viewed science education and training as a ?pipeline" with only one honored endpoint for the student: the replication of the student?s academic mentor, the research professor heading a laboratory in a well-defined scientific discipline. The pipeline model reflects the rigid disciplinary divisions that have existed historically within research universities, as well as a rigid definition of professional success.
Instead of a narrow, unidirectional, and impermeable pipeline, we proposed a new organic paradigm for visualizing science training and careers: a tree with a richly ramifying, highly permeable network of roots and branches reflecting the broad range of inputs into the scientific enterprise and the wide range of career opportunities for students having a solid science background. Postdoctoral fellows are visualized as occupying the trunk and intermediate branches of this ?tree of science." In this new paradigm, optimizing the experience and opportunities of postdocs means aiming to fulfill two quite different, yet complementary, goals.
First, both doctoral and postdoctoral training and education must be redesigned to facilitate advancement in a wide variety of valued positions and careers in industry, education, administration, government, the media, business, and many other domains, in addition to academic research.
Second, organizational policies in many countries must be refined in order to enable the most skilled, talented, and successful young scientists to obtain independent positions--that is, to advance to the tree?s ?upper branches"--at early and highly creative stages of their careers.
This second challenge is generally recognized and is a major cause of ?brain drain" of young scientists from one country to another, particularly to the United States. Indeed, all the nations represented at our Strasbourg meeting have begun to address this issue by establishing innovative programs to promote the transition to independence for their most promising young investigators. Such programs are critical to a nation?s scientific and economic competitiveness. Despite many difficulties, I believe there are strong internal pressures to carry forward and expand these programs within most countries with active scientific research communities.
More germane to the discussion topic of this forum are mechanisms and guidelines needed not only to optimize academic opportunities for selected postdocs, but to provide a broad array of rewarding career opportunities for the majority of postdocs who will not ascend to independent positions in the top branches of the tree. I will outline approaches to this challenge below; a fuller account of all the recommendations arising from our Strasbourg meeting, with selected references, can be found at http://www.hfsp.org/pubs/Position_Papers/FundersReport2002.pdf .
The trunk and intermediate branches of the metaphorical tree of science represent the stages of maturation of the young scientist. It is generally during the years of their postdoctoral fellowship that young scientists have the best opportunity to prove themselves as researchers and sow the first seeds of an independent career. Too frequently, however, postdoctoral fellows are treated as highly skilled and hard-working technical assistants rather than scientific minds in training. Moreover, the academic mechanisms to monitor and guide doctoral candidates? progress are rarely accompanied by equivalent mechanisms to guide postdocs. Student-centered training environments for postdocs as well as graduate students are urgently needed. The postdoctoral mentoring programs developed at the University of Pennsylvania  and other institutions fill an important need and can be adapted through Web-based technologies. Funding agencies should require that all institutions receiving support provide postdoc mentoring and training of the kind outlined in a recent report from the U.S. National Academy of Sciences ( Enhancing the Postdoctoral Experience for Scientists and Engineers, Committee on Science, Engineering, and Public Policy, 2000 ).
From the outset of their training, students should have the opportunity to explore a wide array of fields and to test where their talents and interests lie through a broadly based scientific curriculum. There is now widespread recognition that many scientific research paths, particularly in the life sciences, transcend conventional disciplinary boundaries. Indeed, the current revolution in the life sciences has to a large degree been driven by the availability of new tools developed by physics, chemistry, informatics, and engineering. A number of funding agencies have established model programs that provide interdisciplinary training by faculty from different departments and also offer experiences in a variety of research venues, including industrial settings. With the growth of genomics, proteomics, and other large-scale approaches in the life sciences, an increasing number of large, interdisciplinary groups collaboratively probe many aspects of complex biological systems. This large-scale approach has long been a feature of research in the physical sciences, and it needs to be made a stronger component of training options available to students and postdocs in the life sciences.
At the same time, highly trained scientists who remain in the same research positions for prolonged periods are too often treated as long-term temporary workers or ?permanent postdocs" with poor remuneration, security, and benefits. A stronger, more stable, and more ethical career structure needs to be developed to support researchers who are team members but are not in positions as independent, research team leaders. The Concordat  developed by funders and universities in the United Kingdom provides guidelines for such a structure.
We live in a world increasingly driven by scientific and technological innovation. Never before has there been a greater need for individuals with strong education in the sciences to bring their knowledge, experience, and perspectives to business, government, industry, administration, teaching, journalism, and a host of other fields. Some funding agencies support training programs that include training in administration, teaching, and ethics as ways of enhancing the scientific research enterprise and laying the groundwork for alternative careers. Such programs need to become much more pervasive. An education in science should be seen as excellent preparation for a multitude of diverse careers in which a science education is essential. The Internet provides unprecedented opportunities for communicating information on science-based careers without any geographical restrictions. Indeed, the very existence of Science?s Next Wave and this virtual forum is an encouraging sign that a new ?tree of science" is taking root.
Are there too many postdocs? My own feeling is that the current number of postdocs in the life sciences is about right. Yes, the climb to the upper branches of science is hard and will be attained only by a minority of postdocs. This is part of the risk involved in pursuing a research career--part of the risk involved in all ambitious human endeavors--and I do not believe that policy-makers should react to this freely taken risk through measures that restrict individual choice. I think that the impulse to pursue science as a career is often akin to the impulse that drives a young painter, writer, or dancer--that the impulse to unravel and understand deep patterns in nature is akin to the impulse to create resonant patterns in color, words, or music. The young scientist and artist alike find intellectual and emotional challenges and rewards in their fields that they feel they can find nowhere else; these rewards cannot be quantified, yet they need to be part of our discussion in this forum.
Like many others, I left a career path in medicine to pursue basic biological research. I did so not because basic research offered better opportunities for a secure, independent, well-remunerated position than did medicine; quite the contrary. I did it because I felt that there could be no more exciting way to spend one?s life than exploring the workings and development of the brain, and because I felt that this would be the long-term path to true advances in psychiatric diagnosis and treatments. Yet at the time, I viewed my training in medicine in much the way as I believe we should view training in scientific research: as a tree that branched into a variety of interesting and valued areas of employment.
We must revise our approaches to science education and training to better guide students along many richly branching career paths in addition to academic science. Yet at the same time, we should remember that science at its best is more than just a career; it is a unique human creation that combines competition and cooperation, rationality and imagination, passionate debate and solitary exploration in pursuit of new knowledge for the benefit of humanity.
Torsten Wiesel would like to acknowledge the assistance of Geoff Montgomery in preparing this essay and Danuta Krotoski in preparing the report  on which it is based.