they are told. In "Civil Disobedience," Thoreau remarks that there would be no wars if people would only follow their own consciences and not follow orders mindlessly like ants or Myrmidons. The ants, therefore, are small and petty, greedy for gain, conformist, and mindlessly warlike, all attributes which Thoreau detests. He regards them as the worst possible example for free people, who are capable of living thoughtful, peaceful, nonmaterialistic, self-directed lives.

One of Thoreau’s main points in Walden is that the lives people usually live are filled with hard work but little joy or meaning. We often pursue the path we do because it is conventional, not because it fulfills us. For this reason, Thoreau compares humans to ants, alluding to a myth from Greece in which Zeus created a group of men called the Myrmidons out of ants (Thoreau establishes his literary credentials, as people did at the time, through many references to Classical literature).

Thoreau has looked around at the life of his neighbors. Many farm, many work in professions they don’t enjoy, and many go into debt to buy more material goods simply because it is what everybody else does. In this sense, they are like ants: they have to toil endlessly, and they are no different from anyone else. By living meanly, Thoreau doesn’t mean they are cruel to others, but that they live threadbare, constricted lives, even if they have piles of stuff stored away, because they are not being true to themselves. If they were, they would move from being like ants to behaving like men: thinking for themselves and becoming fully human.

Thoreau went to Walden Pond as an experiment. He wanted to see if he would be happier living as simply and frugally as possible without having to work more than six weeks a year. He discovered joy and contentment through simplicity, so he wrote his book to persuade other people of the value of his path and to show, with financial details, how people could pursue the simple life. We don’t have to live toiling and faceless like ants, he asserts, but can be who we want to be.

Thoreau is referring to the fact that in modern society man unthinkingly allows himself to be a small part of a large collective, just like a worker in a giant colony of ants. And to a staunch individualist like Thoreau that's a pretty sorry state of affairs. He wants us all to affirm ourselves as unique, distinct individuals with the power to think for ourselves and lead the kind of lives we really want to lead instead of blindly going along with what everyone else is doing.

The fable to which Thoreau refers is from Ancient Greek mythology, when Zeus created a race of people called the Myrmidons out of a colony of ants. Thoreau uses this fable to illustrate his point that modern man is reverting to an almost animal-like existence in willingly subjecting himself to the dictates of the collective.

If you look at the definition for "meanly," you will find that it can mean "inferior" or "of little consequence."  Think about the picture that Thoreau creates with the simile comparing man to ants--ants have no higher rank or consequence over another ant; they each do the same repetitive work over and over, without thinking.  

Thoreau gives the reader this simile to discuss how man treats life.  In the same section he says, "Our life is frittered away by detail."  Man allows all of the "things" to get in the way of living an actual life, which is why Thoreau wanted humanity to simplify instead.  When we rid ourselves of all the unnecessary things in our life, when we think about all we feel we have to do instead of focusing on just what is needed, then we are allowing life to take over instead of living it.