Comments on: There’s a big difference between nothing and almost nothing https://www.isegoria.net/2017/09/theres-a-big-difference-between-nothing-and-almost-nothing/ From the ancient Greek for equality in freedom of speech; an eclectic mix of thoughts, large and small Thu, 02 Jul 2026 17:31:58 +0000 hourly 1 http://wordpress.org/?v=3.6.1 By: Wang Weilin https://www.isegoria.net/2017/09/theres-a-big-difference-between-nothing-and-almost-nothing/comment-page-1/#comment-2582036 Wang Weilin Wed, 20 Sep 2017 04:37:55 +0000 http://www.isegoria.net/?p=42392#comment-2582036 “It’s not true that there’s nothing new under the sun.”

This statement is false.

The laws of physics, chemistry, quantum mechanics, thermodynamics, etc., for all purposes here, have been constant for billions of years. The fact the we observe them with human understanding or have learned to use them in the last few centuries doesn’t make them new…just new to us.

]]> By: Jim https://www.isegoria.net/2017/09/theres-a-big-difference-between-nothing-and-almost-nothing/comment-page-1/#comment-2581826 Jim Tue, 19 Sep 2017 15:58:38 +0000 http://www.isegoria.net/?p=42392#comment-2581826 “F=ma” actually tells you virtually nothing. It’s just a tautological definition. The important thing about motion in Newtonian mechanics for say a system of particles is that the “force” in the above equation is always a function of the position and velocity of a moving body and does not involve for example higher derivatives. So F is always given by a function of the position and velocity of the particles involved and the equation “F=ma” reduces to expressing the acceleration of each particle as a function of the positions and velocities of all the particles.

If the “force” F were given as a function involving the second or higher derivatives of the particles involved then formally we could still write “F=ma” but the resulting differential equations would in general be of a totally different type from those actually arising in Newtonian mechanics.

The crucial point of Newtonian mechanics is that the equations of motion are a certain type of second order differential equations. The expression “F=ma” is a formal tautology.

In developing say classical celestial mechanics of point particles one doesn’t even need the concept of “force”. The concept of “force” then adds nothing to the differential equations which determine the motion.

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