 Nothing exists without a sufficient reason for why it exists rather than does not exist. That is, if something is posited to exist, something must also be posited that explains why the first thing exists rather than does not exist. For either (i) nothing exists without a sufficient reason for why it exists rather than does not exist, or else (ii) something can exist without a sufficient reason for why it exists rather than does not exist (§53). Let us assume that some A exists without a sufficient reason for why it exists rather than does not exist. (§56) Therefore nothing is to be posited that explains why A exists. What is more, A is admitted to exist because nothing is assumed to exist: since this is absurd (§69), nothing exists without a sufficient reason; and if something is posited to exist, something else must be assumed that explains why that thing exists.