Here is a famous passage from Ralph Waldo Emerson's "Self-Reliance" rarely quoted in full:
A foolish consistency is the hobgoblin of little minds, adored by little statesmen and philosophers and divines. With consistency a great soul has simply nothing to do. He may as well concern himself with his shadow on the wall. Speak what you think now in hard words and tomorrow speak what to-morrow thinks in hard words again, though it contradict every thing you said to-day. (Ziff, 183)
People routinely rip the initial clause of this passage out of its context and take Emerson to be attacking logical consistency. Or else they quote only the first sentence, or the first two sentences. An example by someone who really ought to know better is provided by Robert Fogelin in his book, Walking the Tightrope of Reason (Oxford UP, 2001). Chapter One, "Why Obey the Laws of Logic?," has among its mottoes (p. 14) the first two sentences of the Emerson quotation above. The other three mottoes, from Whitman, Nietzsche, and Aristotle, are plainly about logical consistency.
It should be clear to anyone who reads the entire passage quoted above in the context of Emerson's essay that Emerson’s dictum has nothing to do with logical consistency and everything to do with consistency of beliefs over time.
The consistency in question is diachronic rather than synchronic. A “little mind” is “foolishly consistent” if it refuses to change its beliefs when change is needed due to changing circumstances, further experience, or clearer thinking. It should be clear that if I believe that p at time t, but believe that ~p at later time t*, then there is no time at which I hold logically inconsistent beliefs.
Doxastic alteration, like alteration in general, is noncontradictory for the simple reason that properties which are contradictory when taken in abstracto are had at different times. My coffee changes from hot to non-hot, and thus has contradictory attributes when we abstract from the time of their instantiation. But since the coffee instantiates them at different times, there is no contradiction such as would cause us to join Parmenides in denying the reality of the changeful world.
Belief change is just a special case of this.
Emerson’s sound point, then, is that one should not make a fetish out of doxastic stasis: there is nothing wrong with being ‘inconsistent’ in the sense of changing one’s beliefs when circumstances change and as one gains in experience and insight. But this is not to say that one should adopt the antics of the flibbertigibbet. Relative stability of views over time is an indicator of character.
Before leaving this topic, let's consider what Walt Whitman has to say in the penultimate section 51 of “Song of Myself” in Leaves of Grass:
Do I contradict myself? Very well then I contradict myself, (I am large, I contain multitudes.)
Here it appears that Whitman is thumbing his nose at logical consistency. If so, the Emersonic and Whitmanic dicta ought not be confused. But confuse them is precisely what Fogelin does when he places the Emerson and Whitman quotations cheek-by-jowl on p. 14 of his book.
That being said, Professor Fogelin is a very good philosopher, and the book I refer to above is well worth your time.