What is Gravity? #gravity #science #physics

If we pick up a stone and then let it go, why does it fall to the ground?” (Albert Einstein, Relativity: The Special and the General Theory, Ch. XIX).

Gravity, of course. But why gravity? One might say it is simply a law of nature, as Isaac Newton discovered. But, even Newton admitted he did not know why there was such a thing:

But hitherto I have not been able to discover the cause of those properties of gravity from phenomena…(De Principia, Bk. III, General Scholium).

Albert Einstein will seek to explain gravity by positing warped space-time. He writes:

…our universe behaves analogously to a surface which is irregularly curved in its individual parts…something like the rippled surface of a lake…the four-dimensional mode of consideration of the “world” is natural on the theory of relativity, since according to this theory time is robbed of its independence…(Einstein, Ibid, Ch. XXXII).

However, Einstein’s theory, by coupling space with time (if true) would seem to implicate a “frozen” or static universe (see footnote for more on this).1 In his own words:

For people like us who believe in physics, the separation between past, present and future has only the importance of an admittedly tenacious illusion (Einstein, Letter to Vero and Brice Rusconi, 1955).
Instead of Einstein, we could take Newton’s all-pervading “Spirit” as the cause of gravity. Newton wrote:

And now we might add something concerning a certain most subtle Spirit which pervades and lies hid in all gross bodies; by the force and action of which Spirit the particles of bodies mutually attract one another at near distances (Newton, Ibid.).
However, this seems dangerously close to pantheism or occasionalism.2

Therefore, in this post, we will relate another theory on gravity, which is of late making a resurgence in contemporary discussions on the topic, namely, Aristotle’s.

Aristotle is also, quite surprisingly, making a resurgence within other areas of physics as well, such as in quantum mechanics. To this point, Werner Heisenberg, Nobel Prize holder in Physics, wrote:

All the elementary particles are made of the same substance, which we may call energy or universal matter…If we compare this situation with the Aristotelian concepts of matter and form, we can say that the matter of Aristotle, which is mere “potentia,” should be compared to our concept of energy, which gets into “actuality” by means of the form, when the elementary particle is created (Physics and Philosophy, Quantum Theory and the Structure of Matter).

And if Aristotle’s thought, albeit 2,400 years old, can have something to say about quantum theory, it may have something to say about gravity as well.
Therefore, let us turn back the clock and ask from an Aristotelian perspective that timeless question: “If we pick up a stone and then let it go, why does it fall to the ground?”