Hume, Enquiry Concerning Human Understanding

SECTION V: Skeptical Solution of these Doubts

Skeptical Philosophy
Philosophical Therapy
Hellenistic schools of philosophy sought tranquility
They engaged in philosophy not so much in the pursuit of truth or meaning or justification, but in pursuit of relief from various types of anxiety
Stoics for example, sought tranquility through removing dissatisfaction (a state in which the world does not fit with one’s desires), and they did philosophy to show that the way to do this is not by trying to change the world to fit our desires but by trying to change our minds/desires to fit the world.
Epicureans sought tranquility through the stability of a moderately pleasurable life that avoids extremes of pleasure and pain, and they used philosophy to undermine sources of anxiety and motivation for seeking extremes--e.g., the fear of death and the desire to please the gods.

Philosophical ‘Rationalizations’
Hume observes that most philosophy (and religion) are subject to a certain ‘inconvenience.’
This inconvenience is that while they promote the perfection of our manners and the cultivation of wisdom they really serve to foster certain ‘predominant inclinations.’
I think this is essentially making the point that philosophies are frequently used to ‘rationalize’ our preconceptions, biases, prejudices, etc.

Academic Philosophy
The one philosophy that is not subject to this inconvenience is that of academic skepticism, since it is explicitly opposed to the “supine indolence of the mind, its rash arrogance, its lofty pretensions, and its superstitious credulity.”
This school also offers a kind of therapy that seeks to remove a source of intellectual anxiety (philosophical puzzlement) by showing the limits of human reason and recommending a suspension of judgment on speculative matters.
Still this moderate skepticism (as opposed to Pyrrhonism) does not try to take the suspension of judgment into ‘common life.’
I think Hume is recommending that we do philosophy academically to purge ourselves of the indolence of mind, rash arrogance, lofty pretensions and superstitions; but we cannot and should not allow skeptical attitudes to “undermine the reasonings of common life.”

Custom
Thought Experiment
A perfectly rational person brought all of a sudden into the world would not be able to reach the idea of cause and effect and would not infer that similar events will have similar effects. This person would not employ his reasoning concerning any matter of fact and so not be assured of anything beyond what was immediately present.
But if that person acquired more experience and observed the constant conjunction of events, he would inevitably began to infer the existence of one from the observation of the other.

Constant Conjunction
Thus the source of beliefs about cause and effect and matters of fact is a psychologic propensity (a kind of conditioning) to develop a habit of belief formation on the basis of the experience of constant conjunction.
The principle of custom seems the only one that can explain why we draw a certain inference (from fire to heat, for example) after a “thousand instances” that we would not draw after one that is “in no respect different from them.”
It is this inferences that allow us to get around in the world in common life.
So custom, and not reasoning, os the “great guide of human life.”

Immediate Perception
Though our inferences about matters of fact carry us beyond what memory and senses provide, there still must be “some fact present to the senses or memory from which we first proceed in drawing these conclusion.”
Our ‘reasons’ for why we believe some matter of fact must ultimately trace back to some fact present to the memory or senses (producing internal or external impressions), for it cannot go back to infinity or else there would be no foundation for our belief.
These foundations in immediate perception do not justify the beliefs but explain them.

Natural Instinct
The mind is carried by custom to make inferences and form beliefs, and it cannot help but do so.
Beliefs are formed simply as the result of placing the mind in certain circumstances.
These operations of the mind are thus species of natural instinct, not the free exercise of some special intellectual faculty.

Belief
Human Understanding
Perceptions
Impressions internal external
Ideas (copies of impressions, arise through association based on...) resemblance contiguity cause and effect
Judgment (beliefs)
Reason: belief formation governed by principles of logic
Sentiment: belief formation governed by principles of psychology
Imagination (fictions)
Belief as a sentiment
Beliefs about matters of fact are not produced by reasoning but by sentiment.
What is the difference between belief and fiction, if it is not that beliefs are justified and fictions not?
The difference is only a matter of degree of sentiment or feeling. Beliefs are more vivd and lively forcible firm and steady
Function of belief: the distinctive feeling of beliefs makes them have more weight and influence appear more useful governing principles of actions