No matter how full a reservoir of maxims one may possess, and no matter how good one’s sentiments may be, if one have not taken advantage of every concrete opportunity to act, one’s character may remain entirely unaffected for the better. With mere good intentions, hell is proverbially paved. An this is an obvious consequence of the principles we have laid down. A ‘character,’ as J.S. Mill says, ‘is a completely fashioned will’; and a will, in the sense in which he means it, is an aggregate of tendencies to act in a firm and prompt and definite way upon all the principal emergencies of life.

☛ The Principles of Psychology by William James, 1890, Vol. I, chap. 4, p. 125. Digitized images of the book are available at the Internet Archive: Vol. I and Vol. II. Both volumes are in the public domain.

Here we have an argument in favor not only of the will, but more precisely of its actualization into actions. What’s worth a will, one may ask, if it doesn’t express itself into actions? “With mere good intentions, writes James, hell is proverbially paved.”
I know of two different perspectives on this subject matter. For one, actions and ideas are inextricably linked or, as James puts it, they should be. For example, I find a similar argument in a recent essay by Slavoj Žižek, “The Un-Shock Doctrine” (published online by the Guernica magazine on May 2011):

As such, it invites us to repeat the passage from Kant to Hegel—to re-conceive the Idea of communism as an Idea in the Hegelian sense, that is, as an Idea which is in the process of its own actualization. The Idea that “makes itself what it is” is thus no longer a concept opposed to reality as its lifeless shadow, but one which gives reality and existence to itself.
[…] What the notion of the Idea as a product of itself makes visible is thus not a process of idealist self-engendering, but the materialist fact that an Idea exists only in and through the activity of the individuals engaged with it and motivated by it.

E.M. Rogers and D.L. Kincaid propose a similar understanding of the relation between actions and idea when they try to rethink the concept of information in their book Communication Nertworks: Toward a New Paradigm for Research (New York: Free Press, 1981; Google Books). The new communication model they are using describes how psychological and physical realities are related in what the authors call “an information circuit”:

In this sense, action is information and all information is the result of action. Thus, we see the unity of action and information. (p. 54)

From the other perspective however, the relationship between actions and ideas is more problematic. I can think of two examples where this point of view is represented. First, in the short novel Notes from Underground written by Fyodor Dostoyevsky and published in 1864. It may be a bold summary, but in my view the protagonist of this story is torned between two opposite behavior: the one who act doesn’t think, while the one who think doesn’t act. Or to put it in other words: the more conscious you are, the less you’re prone to action.
This brings me to my second example, a famous quote by French writer Paul Valéry:

Que de choses il faut ignorer pour « agir » ! (“Choses Tues” 1932, republished in Tel Quel, Vol. I, Gallimard, Pairs, 1941, p. 63)

Which translates as follow:

Of how many things must we be ignorant in order to “act”!

“Choses Tues” was translated as “Asides” published in Analects by Paul Valéry, from The Collected Works of Paul Valéry, vol. 14, edited by Jackson Mathews, translated by W. H. Auden, first published in English in 1970, London: Routledge & Kegan Paul Ltd., p. 43.

Finally, I’m wondering if Giorgio Agamben’s reading of Aristotle regarding potentiality (in his essay on Bartleby) could be read as an in-between position. The potential may or may not actualized itself into action. For Aristotle, one couldn’t think about potentiality without thinking about pure potentiality, that is potentiality without actualization. In other words, James’ celebration of action should logically rise from the acceptance that the will is also fundamentally the will-not-to (do something, spring into action). See “Bartleby, or On Contingency” published in Potentialities, tr. by Daniel Heller-Roazen, Stanford: Stanford University Press, 1999 (Google Books).

I first spotted the excerpt quoted at the beginning of this post while investigating an another one published at Innovation is Dead.