This is a follow-up to "Justification: Divided over Charity", and presumes familiarity with it.
A dead body is not the same thing as a living body. What distinguishes a dead body from a living body is that the former does not have life. A dead body is a body that has lost its life. So, necessarily a living body is a composite of body and life, otherwise, necessarily every body would be a living body.
Likewise, a dead faith is not the same thing as a living faith. What distinguishes dead faith from living faith is that the former does not have life. So, necessarily, living faith is a composite of faith and that which makes faith living; otherwise, there would no such thing as dead faith. But we know that there is such a thing as dead faith. (cf. St. James 2:17, 26) Therefore, living faith is a composite of faith and that which makes faith living.
For this reason, if a person claims that we are not justified by dead faith, and claims that we are justified by faith alone, then we can take this position in two possible ways. Either the position is self-contradictory, since [faith + life] is not "faith alone", or the term 'alone' in "faith alone" should not be taken absolutely, so as to exclude that which makes faith living, but should be taken relatively, so as to exclude something else (e.g. a product of living faith, or something co-present with living faith, but not that by which faith is made to be living). The latter way of understanding the position is more charitable, so that's the way I will understand it.
This factor that makes faith living, call it L (for 'Life'). Now, L cannot be a product of [faith without L], for two reasons. First, dead faith cannot produce anything, being dead, and therefore useless. Second, since nothing can give what it does not have, [faith without L] cannot produce L. Just as a dead body cannot produce life, so [faith without L] cannot produce L.
Not only that, but for faith to be living, L cannot merely be co-present or juxtaposed alongside or simply with faith, for then we would just have L co-present or juxtaposed alongside or with dead faith. Therefore, L has to be informing faith in the same sort of way that a soul informs (i.e. animates) a living body.
This raises three questions for those who hold all three of the following claims to be true: (1) faith alone justifies, (2) dead faith does not justify, and (3) charity does not make faith alive or contribute to making faith alive. First, what is L? Second, what is your evidence that L does not at least contain or include charity? Third, is your evidence for (3) strong enough to warrant forming or perpetuating a schism from those who do not hold (3)?
"I remembered how one of my favorite theologians, Dr. Gerstner, once said in class that if Protestants were wrong on sola fide -- and the Catholic Church was right ... "I'd be on me knees tomorrow morning outside the Vatican doing penance." - Scott Hahn, Rome Sweet Home, p. 31.