Inarguably vs. Arguably — What's the Difference?

Not arguable.

Arguably: Essays is a 2011 book by Christopher Hitchens, comprising 107 essays on a variety of political and cultural topics. These essays were previously published in The Atlantic, City Journal, Foreign Affairs, The Guardian, Newsweek, New Statesman, The New York Times Book Review, Slate, Times Literary Supplement, The Wall Street Journal, The Weekly Standard, The Wilson Quarterly, and Vanity Fair.

Indisputably; certainly, definitely; without the possibility of argument or debate.

Open to argument

Capable of being argued plausibly; defensible in argument

As can be supported or proven by sound logical deduction, evidence, and precedent.

As can be shown by argument;