Language, Truth and Logic by A. J. Ayers, 1952

Content warning: I am not a philosopher.

The Viennese had their turn at logical positivism during the early 20th century, intent on purifying philosophy by purging it of anything not supported by evidence. Ayer, an English philosopher in his early 20s, joined the cause in the early ’30s; by the mid ’30s this book appeared. Ayer’s advance to logical positivism was to weaken evidentiary standards to accept statements as meaningful if they allowed for the possibility of having evidence. A logical positivist says the statement “There are no swimming pools on Jupiter” is meaningless because it is accompanied by no evidence. Ayer assigns the statement meaning because it’s possible, albeit not necessarily practical, to imagine how such evidence could exist. Armed with this and a few other refinements (the non-empirical a priori, probable truth, linguistic equivalences), Ayer goes on to excise swaths of philosophy — metaphysics, aesthetics, ethical inquiry, theological reasoning — and settle long-running debates: rationalism vs empiricism, realism vs idealism, monism vs pluralism, the vexing yet delicate question of the self and others. Later editions have an Introduction, which is better read as an afterword due to forward references, that addresses the critics and makes a few clarifications.

The joke is logical positivism failed (to the extent that a philosophical discipline can be said to fail, as shown by the recent panpsychism revival), and this book lives on as its monument. It’s a pathological book, symptomatic of a young firebrand filled with piss and vinegar for the cause. The writing is clear in its words, but the words are often chained together into sentences and paragraphs of daunting length and structural complexity. The absence of metaphysical underbrush, except for target practice, makes reading relatively simpler, or at least more straightforward (and the metaphysical is still around, but now more like the water through which the little fishies swim). Ayer’s claims are plainly stated and boldly argued; the subtlety comes when figuring out why he isn’t obviously wrong, or why obviously correct matters have any value.