Locke states, “There is not so contemptible a plant or animal that does not confound the most enlarged understanding” (Essay Concerning Human Understanding Bk III, VI, 9). Later he says, “how, vain… it is to expect demonstration and certainty in things not capable of it, and refuse assent to very rational propositions… because they cannot be made out so evident as to surmount every… pretense of doubting” (Essay Bk IV, XI, 10). Locke then establishes belief as a way to “supply our want of knowledge.” The grounds for believing which Locke gives, especially the second being “the testimony of others…” has implications regarding the intellectual defensibility of the Christian faith.
Aquinas wrote something regarding how the limits of our powers of perception and understanding ought to not result in skepticism of anything that cannot be demonstrated, especially in relation to the Christian faith. In the Prologue of his exposition of the Apostles’ Creed (https://dhspriory.org/thomas/english/Creed.htm) he answers the question “what is faith?” Aquinas says, “But someone will say that it is foolish to believe what is not seen, and that one should not believe in things that he cannot see. I answer by saying that the imperfect nature of our intellect takes away the basis of this difficulty. For if man of himself could in a perfect manner know all things visible and invisible, it would indeed be foolish to believe what he does not see. But our manner of knowing is so weak that no philosopher could perfectly investigate the nature of even one little fly.” Given our limited experience and understanding we must often “partake” in the knowledge of a knower. This involves a humble recognition of the limits of our experience and knowledge, and a willingness to be in a relationship of trust with our fellow human beings who have experience and knowledge which we have not. Ultimately, according to Aquinas and Locke, it must direct us to trust in God and his revelation.