To exist means to be in the current state of all point particles. In other words, to be in the present, rather than than the past or the future.

Definition: X is a body if and only if (X exists and X can cease to exist)

Definition: X is a point particle if and only if (X exists and x cannot cease to exist)

Theorem: X exists if and only if (X is a point particle or X is a body)

Suppose X exists(OSC1). Now, either X can cease to exist or X cannot cease to exist(LEM). Suppose X cannot cease to exist(OSC2). Therefore, X exists and X cannot cease to exist(C). Therefore, X is a point particle (def). Therefore, if X cannot cease to exist then X is a point particle (CSC2). Suppose that X can cease to exist(OSC2). Therefore, X exists and X can cease to exist(C). Therefore, X is a body (def). Therefore, if X can cease to exist then X is a body (CSC2). Again, X can cease to exist or X cannot cease to exist(R). Therefore, X is a point particle or X is a body (CDL). Therefore, if X exists then (X is a point particle or X is a body) (CSC1).

Suppose X is a point particle (OSC1). Therefore, X exists and X cannot cease to exist(def). Therefore, X exists(simp1). Therefore, if X is a point particle then X exists (CSC1). Suppose X is a body (OSC1). Therefore, X exists and X can cease to exist(def). Therefore, X exists(simp1). Therefore, if X is a body then X exists(CSC1). Therefore, if X is a point particle or X is a body then X exists(IC).

Therefore, if X exists then (X is a point particle or X is a body), and if X is a point particle or X is a body then X exists(C). Therefore, X exists if and only if (X is a point particle or X is a body) (def3). Thus it has been demonstrated.

We can connect this article to the branch of philosophy known as materialism, by introducting the following definition of matter:

Definition: X is matter if and only if (X is a point particle or X is a body).

Materialism is the philosophy that only matter exists. This philosophy is consistent with the definition of existence given at the start of this article. Notice that the definition of existence was temporal in nature, yet using the definitions of 'point particle' and 'body' above, the conclusion that "X exists if and only if X is matter" can be deductively reached.