asks @RSessions (Roger Sessions)
I have long argued that the answer is no. What passes for knowledge in enterprise architecture is largely a combination of anecdote and received opinion. Intellectual effort is devoted to hierarchical forms and elaborate classification schemas, based on abstract reason rather than empirical measurement; this kind of work looks more like mediaeval scholastic philosophy than modern science.
In comparison, the followers of Christopher Alexander seem like nineteenth century gentleman scientists, carefully collecting specimens from which they try to infer useful principles and patterns. Alexander's four-volume masterpiece on the Nature of Order is a brilliant and fascinating work, which I think every enterprise architect should read (in their spare time), but it's not exactly suitable as an everyday handbook.
In order for enterprise architecture to qualify as a science, it has to follow scientific method. Now I am pretty broadminded about what counts as scientific method, but it's more than mere predictability. (Card games are predictable, but that doesn't make cribbage a science. Roger says if card games were predictable, he'd be a rich man. But if card games were not predictable, the casinos would go broke.)
Anyway, you can get predictability from art. I saw Dave Crosby on a documentary once, criticizing the fact that the Eagles' concerts were note-for-note predictable, CSNY preferring a slightly looser style in response to each audience. So what if EA's an art, asks @HotFusionMan (Al Chou).
Peirce understood the limitation of scientific method, holding "that slow and stumbling ratiocination can be dangerously inferior to instinct, sentiment, and tradition in practical matters" (Wikipedia).
So does it matter if (as I believe) Enterprise Architecture is not a science? The key question that raises is - what is the source and status of EA knowledge, and how can we ever resolve matters of opinion, except by obscure mediaeval argument?
Follow-up post Is Enterprise Architecture a Science (2)?