"Dark Matter" and "Dark Energy" are both names for observed effects. They're not specific theories. E.g. MOND is a theory to explain dark matter without needing

"Dark Matter" and "Dark Energy" are both names for observed effects. They're not specific theories. E.g. MOND is a theory to explain dark matter without needing a new particle or field. It doesn't explain as much as λCDM, but what it does explain it does without new fields. That's aesthetically pleasing to some people.