A Treatise of Human Nature

“Now since all ideas are deriv’d from impressions, and are nothing but copies and representations of them, whatever is true of the one must be ackowledg’d concerning the other. Impressions and ideas differ only in their strength and vivacity.”

This is where Hume lays out the definitions of impressions and ideas and what the differences between the two are. Also, Hume introduces what would prove to be a common theme in A Treatise of Human Nature, which is how ideas and impressions are judged by their strength or what Hume calls “vivacity.”

“Wherever ideas are adequate representations of objects, the relations, contradictions and agreements of the ideas are all applicable to the objects; and this we may in general observe to be the foundation of all human knowledge.”

If Hume lays out the thesis for A Treatise of Human Nature anywhere, it is with this passage. This passage serves as a definition for empiricism in general: that our knowledge is derived from the information we gain from our senses and direct observation.

“Whatever can be conceiv’d by a clear and distinct idea necessarily implies the possibility of existence; and he who pretends to prove the impossibility of its existence by any argument deriv’d from the clear idea, in reality asserts, that we have no clear idea of it, because we have a clear idea. ’Tis in vain to search for a contradiction in anything that is distinctly conceiv’d by the mind.”

In this passage, Hume means that we cannot imagine something that cannot exist. Even beings straight out of fiction, like a cyclopes, can be broken down into ideas and perceptions that already exist in reality.

“[T]he idea of space or extension is nothing but the idea of visible or tangible points distributed in a certain order.”

This is an example of what Hume means by observation. Even with more abstract ideas like a geographical concept, we can at least demonstrate some geographical concept through drawing lines and points.

“Now since nothing is ever present to the mind but perceptions, and since all ideas are deriv'd from something antecedently present to the mind; it follows, that 'tis impossible for us so much as to conceive or form an idea of anything specifically different from ideas and impressions.”

Hume continues his argument that, even with an imagination, we are limited to our ideas and impressions. An example of this that Hume gives is a mountain with a valley, which does not exist in reality therefore it is beyond our ability to imagine (81).

“’Tis therefore by EXPERIENCE only, that we can infer the existence of one object from that of another.”

This is another point where Hume speaks out in favor of empiricism. Only direct experience allows us to be able to identify and perceive the differences between objects.

“[W]hen any impression becomes present to us, it not only transports the mind to such ideas as are related to it, but likewise communicates to them a share of its force and vivacity.”

Hume sees impressions and ideas as deeply connected with each other. The more vivid the impression, the stronger the idea based on it.

“First we may observe, that the supposition, that the future resembles the past, is not founded on arguments of any kind, but is deriv’d entirely from habit, by which we are determin’d to expect for the future the same train of objects, to which we have been accustom’d.”

Hume challenges our views of cause and effect here. Specifically, Hume rejects the idea that we can rely on the assumption that events in the present or future are necessarily related to events in the past.

“Belief, being a lively conception, can never be entire, where it is not founded on something natural and easy.”

Hume defines belief as an idea that is particularly strong or “lively.” However, Hume struggles with theorizing what makes an idea into a belief (146). Still, the simpler the judgment or perception the belief is based on, the stronger the belief is.

“[W]e may observe, that what we call a mind, is nothing but a heap or collection of different perceptions, united together by certain relations, and suppos’d, tho’ falsely, to be endow’d with a perfect simplicity and identity.”

One of Hume’s most challenging and controversial arguments is that there is no real such thing as a self. Instead, the self is our constantly changing ideas and their relations with each other.

“Thus neither by considering the first origin of ideas, nor by means of a definition are we able to arrive at any satisfactory notion of substance; which seems to me a sufficient reason for abandoning utterly that dispute concerning the materiality and immateriality of the soul, and makes me absolutely condemn even the question itself. We have no perfect idea of anything but of a perception. A substance is entirely different from a perception. We have, therefore, no idea of a substance.”

Hume’s skepticism leads him to question how we can have an accurate idea of the world around us. Also, Hume explains why he considers questions about intangible things, like the soul, to be pointless.

“Tho’ pride and humility are directly contrary in their effects, and in their sensations, they have notwithstanding the same object; so that ‘tis requisite only to change the relation of impressions, without making any change upon that of ideas. Accordingly we find, that a beautiful house, belonging to ourselves, produces pride; and that the same house, still belonging to ourselves, produces humility.”

In Hume’s views of the emotions, he argues that even opposite emotions like humility and pride have similar origins and operate in similar ways. Pride and humility both are connected between our idea of ourselves and some external object.

“No quality of human nature is more remarkable, both in itself and in its consequences, than that propensity we have to sympathize with others, and to receive by communication their inclinations and sentiments, however different from, or even contrary to our own.”

Sympathy is Hume’s explanation for how we manage to have strong feelings even for people we have never met. For example, Hume might describe our feelings of nationalism and patriotism as a product of sympathy.

“I say then, that nothing can produce any of these passions without bearing it a double relation, viz. of ideas to the object of the passion, and of sensation to the passion itself.”

Hume is careful to explain how even something intangible like emotion can be caused by sensory experience. In such cases, these “objects” are formed through the relations of ideas.

“Upon the whole, there remains nothing, which can give us an esteem for power and riches, and a contempt for meanness and poverty, except the principle of sympathy, by which we enter into the sentiments of the rich and poor, and partake of their pleasure and uneasiness.”

For Hume, sympathy explains how we can relate to people’s experiences, even when we understand those experiences only on an abstract level. It is through sympathy that we admire wealth and celebrity.

“So little are men govern’d by reason in their sentiments and opinions, that they always judge more of objects by comparison than from their intrinsic worth and value.”

Throughout A Treatise of Human Nature, Hume not only makes a case for empiricism, but also argues against nationalism. One of Hume’s points is that people are actually rarely, if ever, motivated by logic and abstract reason.

“’Tis only upon the principles of necessity, that a person acquires any merit or demerit from his actions, however the common opinion may incline to the contrary.”

Necessity determines how much value or blame a person’s actions receive in the eyes of others. For example, we have more esteem for someone who manages to become a successful politician despite coming out of poverty than someone who succeeds in politics while coming from a wealthy background.

“Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them.”

One of the more famous quotes from A Treatise of Human Nature, this passage sums up Hume’s attitude toward the traditional argument that reason and the emotions are always in conflict. Instead, the way we reason is based around our emotions.

“’Tis not contrary to reason to prefer the destruction of the whole world to the scratching of my finger. ‘Tis not contrary to reason for me to chuse my total ruin, to prevent the least uneasiness of an Indian or personal wholly unknown to me.”

This is another famous or notorious passage from A Treatise of Human Nature. Hume dramatically shows how even abstract reason, not the emotions, can lead a person to clearly absurd conclusions.

“Actions may be laudable or blameable; but they cannot be reasonable: Laudable or blameable, therefore, are not the same with reasonable or unreasonable.”

This passage reflects Hume’s overall argument that virtues and vices are mostly determined by how they affect our social relations (660-61). Our vices and virtues are not actually judged through reason.

“In every system of morality […] I am surpriz’d to find, that instead of the usual copulations of propositions, is, and is not, I meet with no proposition that is not connected with an ought, or an ought not. This change is imperceptible; but is, however, of the last consequence. For as this ought, or ought not, expresses some new relation or affirmation, ’tis necessary that it shou’d be observ’d and explain’d […] [I] am persuaded, that a small attention [to this point] wou’d subvert all the vulgar systems of morality, and let us see, that the distinction of vice and virtue is not founded merely on the relations of objects, nor is perceiv’d by reason.”

This sets up one of the more famous concepts from Hume’s philosophy, the is-ought problem. What exactly Hume means here has been debated by modern philosophers and historians, but it is generally thought that Hume is demonstrating that it is difficult, if not impossible, to go from a factual statement of what is with a statement about how things should or should not be.

“As numerous and civiliz’d societies cannot subsist without government, so government is entirely useless without an exact obedience.”

Hume does argue that the subjects of a government should resist when that government becomes tyrannical (614). Still, because the purpose of the government is to ensure the smooth functioning of a society and the legal contracts that bind it together, Hume believes that people should only resist when it becomes obvious the government has become tyrannical.

“The minds of all men are similar in their feelings and operations; nor can anyone be actuated by any affection, of which all others are not, in some degree, susceptible.”

In A Treatise of Human Nature, Hume stresses how each individual gains their knowledge through experience and observation. Nonetheless, Hume asserts that the way we process impressions and ideas is similar across people.