The universe is transformation: life is opinion.
 Marcus Aurelius, Meditations (c. 170 - 180). copy citation

add
Author Marcus Aurelius
Source Meditations
Topic opinion life
Date c. 170 - 180
Language English
Reference
Note Translated by George Long
Weblink https://www.gutenberg.org/files/15877/15877-h/15877-h.htm

Context

“One is that things do not touch the soul, for they are external and remain immovable; but our perturbations come only from the opinion which is within. The other is that all these things, which thou seest, change immediately and will no longer be; and constantly bear in mind how many of these changes thou hast already witnessed. The universe is transformation: life is opinion. [A] Tecum habita, noris quam sit tibi curta supellex.—Perseus, iv. 52.
4. If our intellectual part is common, the reason also, in respect of which we are rational beings, is common: if this is so, common also is the reason which commands us what to do, and what not to do; if this is so, there is a common law also; if this is so, we are fellow-citizens; if this is so, we are members of some political community; if this is so, the world is in a manner a state.” source