“An Enquiry Concerning Human Understanding” by David Hume

This is a big book in the traditional sense. It aims to solve the biggest problems in life- the very nature of humanity. Hume’s first distinction is the relationship between impressions and ideas in the mind. He states that simple impressions always precede simple ideas. “All our ideas are nothing but copies of our impressions, or, in other words, that it is impossible for us to think of any thing, which we have not antecedently felt, either by our external or internal senses.” Furthermore, “our authority over our sentiments and passions is much weaker than that over our ideas.” Hume also separates knowledge between that derived from reason and that derived from experience. He states that although two plus two must always equal four, even the fact that the sun will rise tomorrow is just a strong probability derived from past experience and custom and not an a priori fact. Not only adult humans adjust their lives based on custom, but so do animals and small children, who are not capable of higher-ordered reasoning. Beliefs are gathered from observations or innate instincts, but not through abstract thought.

Hume proceeds to dismantle religious belief in the most obtuse ways possible, to avoid either giving offense or being branded an atheist himself. First, he picks apart the miracles of the Bible by saying that any reasonable person would have to declare that the probability of their actually happening was slim. In fact, he notes that were this not the case these phenomena would not be, by definition, miracles, but would just accord with the common laws of nature. “No testimony is sufficient to establish a miracle unless the testimony be of such a kind that its falsehood would be more miraculous than the fact which it endeavours to establish.”

Hume ends with a defense of moderate Cartesian doubt, “this species of scepticism, when more moderate, may be understood in a very reasonable sense, and is a necessary preparative to the study of philosophy, by preserving a proper impartiality in our judgements, and weaning our mind from all those prejudices, which we may have imbibed from education or rash opinion. To begin with clear and self-evident principles, to advance by timorous and sure steps, to review frequently our conclusions, and examine accurately all their consequences; though by these means we shall make both slow and a short progress in our systems; are the only methods, by which we can ever hope to reach truth, and attain a proper stability and certainty in our determinations.” However, he warns against a too fervent Pyrrhonism, where doubt cripples any human action and everyday commonsense.