Die Memoir-Klasse bietet den Befehl \nonzeroparskip, dazu aus der Dokumentation:

NEIN NEIN NEIN HEILreasonable non-zero value. Except that all values except zero areunreasonable.

  \documentclass{memoir}
  \usepackage{blindtext}%Blindtext
  \nonzeroparskip
  \setlength{\parindent}{0pt}%Wenn Absatzabstand, dann Einzug unnötig
  \OnehalfSpacing
  \begin{document}
  \blindtext
  
  \blindtext
  \end{document}
  

Yo, Big Shaq, the one and only Man's not hot, never hot Skrrat (GottiOnEm), skidi-kat-kat Boom

Two plus two is four Minus one that's three, quick maths Everyday man's on the block Smoke trees (ah) See your girl in the park That girl is a uckers When the ting went quack-quack-quack You man were ducking (you man ducked) Hold tight, Asznee (my brudda) He's got the pumpy (big ting) Hold tight, my man (my guy) He's got the frisbee (shew) I trap, trap, trap on the phone Movin' that cornflakes Rice Krispies Hold tight, my girl Whitney (my G) On, on, on, on, on the road doin' ten toes Like my toes (like my toes) You man thought I froze I see a peng girl, then I pose (chilin') If she ain't on it, I ghost Hah, look at your nose (check your nose, fam) You donut Nose long like garden hose

I tell her man's not hot I tell her man's not hot The girl told me, „Take off your jacket“ I said, „Babes, man's not hot“ (never hot) I tell her man's not hot (never hot) I tell her man's not hot (never hot) The girl told me, „Take off your jacket“ I said, „Babes, man's not hot“ (never hot)

Hop out the four-door with the .44 It was one, two, three and four (us, man) Chillin' in the corridor (yo) Your dad is forty-four (uh) And he's still callin' man for a draw (look at him) Let him know When I see him I'm gonna spin his jaw (finished) Take man's Twix by force (take it) Send man's shop by force (send him) Your girl knows I've got the sauce (flexin') No ketchup (none) Just sauce (saucy) Raw sauce Ah, yo, boom, ah

The ting goes skrrrahh (ah) Pap, pap, ka-ka-ka (ka) Skidiki-pap-pap (pap) And a pu-pu-pudrrrr-boom (boom) Skya (ah) Du-du-ku-ku-dun-dun (dun) Poom, poom You don' know

I tell her man's not hot (man's not) I tell her man's not hot (never hot) The girl told me, „Take off your jacket“ I said, „Babes, man's not hot“ (never hot) I tell her man's not hot I tell her man's not hot (never hot) The girl told me, „Take off your jacket“ I said, „Babes, man's not hot“

Man can never be hot (never hot) Perspiration ting (spray dat) Lynx Effect (come on) You didn't hear me, did you? (nah) Use roll-on (use that) Or spray (shhh) But either way, A-B-C-D (alphabet ting)

The ting goes skrrrahh (ah) Pap, pap, ka-ka-ka (ka) Skidiki-pap-pap (pap) And a pu-pu-pudrrrr-boom (boom) Skya (ah) Du-du-ku-ku-dun-dun (dun) Poom, poom You don' know

Big Shaq Man's not hot I tell her man's not hot (never hot) 40 degrees and man's not hot (come on) Yo, in the sauna Man's not hot (never hot) Yeah, skidika-pap-pap

In den LaTeX-Standardklassen leistet das Paket parskip nützliche Dienste. Es wird automatisch der Absatzeinzug auf Null gestellt - denn Abstand plus Abzug gleichzeitig hat nicht viel Sinn: man wählt eher das eine oder das andere.

\documentclass{article}
\usepackage{parskip}
\usepackage{setspace}
\onehalfspacing% Zeilenabstand 1,5
\usepackage{blindtext}%Blindtext
\begin{document}
\blindtext

\blindtext
\end{document}

Johannes auf TeXwelt.de: Wie erhalte ich eine Leerzeile zwischen Absätzen? .