Faith and religion are different things to different people. I’ve come to the conclusion that dictionary definitions are pretty useless to define faith, god, religion. The dictionary definition is only, at best, a snapshot of different ways people use a word at a particular point in time. And at worst, it shows the biases of the editing committee, or whoever writes those definitions. Therefore the dictionary is a useful guide, but not an authority.
And words like faith and religion, which are highly emotionally charged, have many different (possibly even contradictory) meanings to different people. When atheists criticize ‘faith’ what I have seen is that what they mean by faith is uncritical and unexamining belief that some proposition is true–regardless of any evidence to the contrary. I think this perception of faith is legitimate in that belief is a core element of Christianity and any knowledge that poses a challenge a Christian’s belief is, to some Christians at least, highly feared. (This, I think, is a huge reason many Christians don’t want the Theory of Evolution to be taught in schools. They don’t want their teenagers exposed to something that might cause them to question the biblical account–or maybe even the whole of Christianity. Their very souls are at stake, after all.) This view of faith means sticking your fingers in your ears in the face of contrary evidence and saying “na na na na naa naa I can’t hear you!” But this gets really tricky because of the many definitions of the word ‘faith.’ It also means things to people that have little to do with belief in propositions–things like trust and loyalty. Someone who is true to their spouse is ‘faithful,’ etc. So there is a huge danger of equivocation here. That is when you use a word to mean one thing in part of an argument and something else later in the argument.
Here is a decent example from http://www.logicalfallacies.info/ambiguity/equivocation/.
(1) Christianity teaches that faith is necessary for salvation.
(2) Faith is irrational, it is belief in the absence of or contrary to evidence.
(3) Christianity teaches that irrationality is rewarded.
This argument, which is a reasonably familiar one, switches between two different meanings of “faith”. The kind of faith that Christianity holds is necessary for salvation is belief in God, and an appropriate response to that belief. It does not matter where the belief and the response come from; someone who accepts the gospel based on evidence (e.g. Doubting Thomas) still gets to heaven, according to Christianity.
So faith does not automatically mean irrationality. I think it has come to that connotation in modern times as we learn more and more facts about the world. I’ve heard it said that there will never again be theologians like Thomas Aquinas and others who were the top scholars of their day. All the facts that they knew about the world seemed to confirm the teachings of the Church. Of course the universe must have a designer, which was God! Of course the sun revolved around the earth, as we can clearly see with our own eyes! But now we know more about the universe than Aquinas and company ever dreamt of knowing. There was no tension between the scientific and religious views of their day. They had faith, and it was rational faith.
But does true religious faith really allow for changes in one’s whole view of the world with new learning? Even for the letting go of treasured dogmas when they no longer make sense? Could a Christian be convinced that Jesus’s resurrection was mythical if the historical evidence really points that way–but still have faith? Can a Christian also be a Freethinker (that is, someone who forms their opinions on the basis of reason, not religious creeds)? Can Infidels have faith? Many people, both atheists and believers, seem not to think so.
So why do I care? I actually rather like the word faith in it’s non-irrational connotations. I like the definitions having to do with loyalty, trust, and strong conviction. These are highly compatible with the secular way of life. It’s just the bit about using that same word to also mean dogmatic belief in improbable and improvable tenants that I find highly repulsive.