Why did some European scientists object to Newton’s idea of gravity acting across empty space?

Some European scientists, particularly those on the Continent who adhered to the mechanical philosophy of René Descartes, objected to Isaac Newton’s theory of gravity because it relied on the concept of "action at a distance".12

In the 17th century, the prevailing mechanical philosophy sought to explain all physical phenomena through direct contact between bodies, such as collisions or the movement of matter within vortices. Because Newton could not provide a physical mechanism to explain how gravity could reach across empty space to affect another object, his theory was criticized by some as a return to "occult" qualities or medieval animism.3142

While figures like Christiaan Huygens acknowledged the mathematical success of Newton’s conclusions, they remained skeptical of the idea that an attractive force was an inherent property of matter, preferring instead to search for a physical agent that could account for the interaction.1