Louis Claude de Saint-Martin (1743-1803) was a striking and influential figure in his time. Of Errors & Truth is his first work, published under the pseudonym "The Unknown Philosopher". In it, he develops a critique of the then-fashionable Enlightenment and Encyclopedist empiricism and materialism, from the point of view of an esoteric and Platonic form of Christianity. Pseudonymous though it was, the book made his reputation.

In this book, he argues against the idea that all knowledge, and all social forms, are built up from sensory experience and contingencies of life by a process of abstraction and adaptation. One of the key principles of his argument goes back at least to Plato's Meno: that knowledge is possible only because of innate or pre-existing ideas or forms of experience. In other words, abstraction from the stream of immediate events and experiences must inevitably be guided by some pre-existing target, not itself given in the stream of concrete events, but brought to it by the experiencing and inquiring mind.

The author pursues this theme through a variety of domains, from metaphysics through politics and natural sciences, some times more effectively than others. In this work he was still very much the student of his teacher, Martines de Pasqually, whose methods he later abandoned to follow a more interior path. However, the seeds of this later orientation can be seen in this first book, with its stress on what is already and always available within.

Despite his extensive influence on European esotericism, little of Saint-Martin's work has been available in English, and this translation is an important contribution to filling this gap. The translator has done extensive prior work in making French esoteric texts available in English, and has worked valiantly to do so with this book as well. Unfortunately, the translation suffers from several peculiarities that make it less readable than it could be.

First, there are some serious flaws in proof-reading, leading to breaches in continuity that require a good deal of thought to reconstruct, when that is possible.

Second, the editorial decision to use contractions whenever possible, no doubt to avoid unnecessary stuffiness in an already dense text, has been applied more mechanically than mindfully, especially with "it's", making certain passages ludicrous or even unintelligible. For example, the first line of the second paragraph on page 63 should be "precious though it is", but appears as "precious though it's" -- as though search and replace had been used on every instance of "it is", without regard to meaning.

Finally, there are occasional mistranslations of technical terms – for example, there is an extensive discussion of the best way to translate term "étendue", but it's pretty clear from the context that Saint-Martin is referring to the Cartesian idea of extension as a property of matter (res extensa), a point that does not enter into the discussion.

In other words, the translation reads as though a very competent first draft had gone directly to press, without having had a thorough proof-reading, or the attentions of an outside reader. It would be a noble contribution if a small group of friends of Saint-Martin were able to meet regularly and read the text aloud, compiling an account of all the infelicities, and communicating them to the translator to assist in preparing a revised edition. ( )