For Thoreau, wisdom can't be found in college, or by calling Dr. Phil. Wisdom isn't the same as common sense. In fact, wisdom will often appear nonsensical to the unwise. And wisdom isn't the same as conventional wisdom, since true wisdom will often seem idiosyncratic (too particular) or just plain odd to most of the world.
Now that we've discussed what wisdom is not, let's talk about what it is. Thoreau proposes that true wisdom is unique to each individual, and that it is out there for each individual to discover in practice, through the experiment of living. This search for wisdom should not be confused with selfishness. It's more the development of an inner sense of what is just and right. Since wisdom is unique to each individual, we cannot expect each person's expression of wisdom to be the same as any other's. Every individual expresses wisdom in an equally unique style. For Thoreau, this multiplicity of perspectives is something to be celebrated. Shmoop feels the same way.
At the end of Walden, Thoreau is far wiser than he was when he set out on his "experiment."
The ending of Walden seems to confirm Thoreau's instinct that led him to Walden Pond in the first place. He ends the book just as critical of society and individualistic as he was in the beginning.