Gunnar's research is primarily in the philosophy of biology. It focuses on topics like biological individuality, species, and both modern and historical accounts of teleology. He has published in both philosophical and biological journals such as the British Journal for the Philosophy of Science, Synthese and the Biological Journal of the Linnean Society. He has also presented his work at venues including the Linnean Society of London and the Philosophy of Science Association, and he has written for Aeon Magazine. Currently, he collaborates with Daniel W. McShea (Duke University) to further develop a new approach to understanding goal directed systems that they call field theory. They have been awarded a grant by the John Templeton Foundation to fund a project called Purpose, Agency, and Field Theory,  which is a continuation of this work. Some of Gunnar's other research considers developments in synthetic biology, biological concepts like bio-indeficiency, and various areas of biotechnology to determine how these alter the metaphysical underpinnings of concepts like reproduction, species, and lineages. His broader philosophical interests extend to the history and philosophy of science, environmental ethics and ancient philosophy.