Impetus and Energy

August 11th, 2006 Fred McVittie Posted in Energy, Naive Physics, Newton, Isaac, Physics, Substance |

Naive Physics cannot handle abstract (non-embodied) concepts (in that sense Naive Physics is an organised system of embodied metaphors). Therefore a concept such as ‘energy’ cannot figure with Naive Physics as it does within rational physics, as a purely mathematical or other abstraction. Instead it is conceived of as a SUBSTANCE; a limited resource which provided motive power and which, in common with physical substances, can be transformed, transferred, accumulated, depleted, much as a fuel is conceived in engineering. The Impetus Theory of energy and motion, which is part of the Naive Physics perplex, (and was a part of mainstream ‘rational’ physics from Aristotle onwards) makes explicit use of this ENERGY=FUEL metaphor. This historical correspondence between naive and rational physics was only broken in the 17th century by Newton in his formulation of the laws of motion. In Newton’s schema, motion is conceived not as an unusual state of matter requiring a fuel or impetus to maintain, but as a natural relative state or property. The only ‘energetic’ principle that is required within the Newton paradigm is during acceleration and deceleration, and this cannot be conceived as the transfer of a limited fuel resource into the body of the moving object.