In the late 1800’s, physicists thought that the problems of physics had been mostly solved. After all, Newton’s laws described the motion of ordinary objects, Maxwell’s equations explained electricity and magnetism, and thermodynamics detailed the relationship between forms of energy. But that view of the world soon changed as special and general relativity altered our views of space, time, and gravitation; statistical mechanics provided a stochastic basis for understanding bulk properties of matter; and quantum mechanics blurred the lines between particles and waves, matter and energy. The biological sciences are entering a similar phase of transition between what was and what will be our view of the world and the way it operates. The Human Genome Project has been long heralded as the means to understanding how we as beings carry on the biological processes we need to survive. Sure, if you read the papers you know that the genome sequencing has been declared finished—but we have a long way to go before the promise of the genome project is complete.

First, we don’t yet have a complete catalog of all of the human genes and their variants, and even our understanding of what a gene *is* continues to change as new data becomes available, leading us back to the somewhat vague but all encompassing original definition: a gene is a unit of heredity. And if the gene list remains incomplete, the list of proteins that are the final end product of most of the genes (at least the ones we can agree are genes) is woefully incomplete. Second, even if we were to convince ourselves that these “parts lists� were close to being finished, the “wiring diagram� showing us how they all fit together has not begun to be assembled in any real way. Sure, we can put up wall-sized posters of biological pathways, but these seem to only be the tip of the iceberg. What we are coming to realize is that one gene can have many functions—and one function can often be carried out by many genes. And not only are there pathways, but these pathways are intertwined into networks that seem to have “small world� structures that make the overall connectivity between elements much greater than we would have expected. Third, we have begun to realize that looking at millions of cells (what we typically address in laboratory experiments) is only giving us an average picture of what is happening in an organism and not telling us about what is driving the responses we see. At some level, we are coming to understand that there are stochastic events occurring in cells that are producing the responses we can measure.

Despite all of this—or more likely because of it—the biological sciences are the most exciting place to be working at the present time. Sure, string theory may hold the answers to the ultimate questions of the universe—but we can’t do the fundamental experiments to test it. On the other hand, this biological revolution is driven by technological innovations that are allowing us to do experiments that only a short time ago we could not even dream of. The challenges for us now are to push the technologies and develop new approaches to decoding the data so that we can tie what we see to the biology we so desperately want to understand. We may not unravel the meaning of life, but we are getting closer to understanding what it is and how it works.