1) Chew over 2) Contemplate 3) Excogitate 4) Meditate 5) Mull 6) Mull over 7) Muse 8) Ponder 9) Reflect 10) Ruminate 11) Speculate 12) Think over 13) To engage in introspection 14) To look into 15) To practice introspection 
• (v. t.) To look into or within; to view the inside of.
In`tro·spect' transitive verb [ Latin introspectus , past participle introspicere to look into; intro within + specere to look. See Spy .] To look into or within; to view the inside of. Bailey. 
[v] - reflect on one`s own thoughts and feelings
verb reflect on one`s own thoughts and feelings
to practice introspection; consider one's own internal state or feelings.