Prior to joining the Hofstra faculty, Professor Walker was a partner in the Washington, D.C., law firm of Swidler & Berlin. His practice included representation before state and federal administrative agencies and before courts on judicial review of agency actions. His administrative practice focused primarily on issues concerning public health, safety, and the environment. He also represented clients in civil litigation alleging products liability and toxic torts.
Professor Walker has a doctorate in philosophy, with specialization in knowledge theory, artificial intelligence, deductive and inductive logic, and the conceptual foundations and methodologies of the sciences. His doctoral dissertation was on the perception of objects by biological and mechanical systems. While in law practice, he worked extensively with expert witnesses and scientific evidence, and he co-authored the book Product Risk Reduction in the Chemical Industry. Since joining Hofstra, he has published extensively on the logic of legal reasoning and factfinding, on the design of factfinding processes, and on the use of scientific evidence in legal proceedings. His writings explore the substantive topics of risk assessment, risk management, and scientific uncertainty.
At Hofstra, Professor Walker teaches courses in scientific evidence, torts, products liability, administrative law, and European Union law. He is on the editorial board of the journal of Law, Probability and Risk, and is a past President of the Risk Assessment and Policy Association. He has been a consultant to both private and governmental institutions, in both the United States and in Europe. He also designs computer software that captures legal knowledge and models legal reasoning, and he explores ways to use logical analysis and artificial intelligence in his teaching.