The Platonic dialogues that are built around the death of approach to knowledge, wisdom, and spiritual growth by valorizing the philosophical turn of mind above all as the ultimate human value and valuing mind over matter. Virtually everything is subordinate to wisdom. In the Euthyphro and Apology, the search for wisdom eliminates what knowledge and wisdom are definitely not. In the Phaedo Plato develops the idea that intangible attributes--such as beauty, justice, knowledge, spirituality, and truth--can never reach sense experience but can only be approximated, by way of the soul, an attribute of mind:
Don't you think that the person who is most likely to achieve [knowledge] flawlessly is . . . with the unaided intellect
. . . by applying his pure and unadulterated thought to the pure and unadulterated object, cutting himself off as much as possible from . . . his body" (Phae. 127).
In Walden, Thoreau also is cutting himself off from the material things of the world, but chiefly as they relate to wealth and industry. He wants to use nature instrumentally as a mechanism of transcending material details and to a higher plane of consciousness. In his essay "Economy" in particular, Thoreau valorizes his personal experience at the pond, but his descriptions of building a home and furniture and raising and cooking his own food suggest that experience close to natural simplicity condemn the "coarse labors of life" (109) that are responsible for the fact that the "mass of men lead lives of quiet desperation." Life is "worst of all when you are the slave driver of yourself" (110). Thoreau's solitary experiment in self-sufficiency in terms of physical labor is not to be taken as coarse labor but only a joy in enacting the idea of simplicity.
By the words, necessary of life, I mean whatever, of all that man obtains by his own exertions, has been from the first, or from long use has become, so important to human life that few, if any...