4: Unphilosophical Probability From Hasty General Rules

4. Another unphilosophical kind of probability is that derived from hasty general rules, which:

• we rashly form to ourselves, and
• are the source of prejudice.

An example is: “An Irishman cannot have wit and a Frenchman cannot have solidity.”

The conversation of the:

• Irishman may be visibly very agreeable.
• Frenchman may be very judicious.

But we have entertained such a prejudice against them.

• They are stupid in spite of sense and reason.

Human nature is very subject to errors of this kind.

I think prejudice proceeds from those very principles which all judgments on causes and effects depend on.

Our judgments on cause and effect are derived from habit and experience.

When we have been used to see an object united to another, our imagination transits from the first to the second naturally.

This transition:

• precedes reflection, and
• cannot be prevented by reflection.

Habit naturally:

• operates with its full force when the presented objects are exactly the same with those that we have been used to, and
• operates in an inferior degree when we discover objects to be similar but not exact.

The habit loses its force by every difference.

Yet it is seldom entirely destroyed if any considerable circumstances remain the same.

A man who is used to eating fruits, such as pears or peaches, will satisfy himself with melons if he cannot find his favourite fruit.

A man who gets drunk with red wines will get almost as drunk with white wine if given to him.

From this principle, I have accounted for the species of probability which we derive from analogy.

Through analogy, we transfer our experience in past instances to objects which are resembling, but are not exactly the same with those objects we have experienced.

The probability reduces as the resemblance decays.

But still has some force as long as there remain any traces of the resemblance.

We may carry this observation further.

Habit is the foundation of all our judgments.

But sometimes, habit opposes judgement in the imagination.

It produces a contrariety in our feelings on the same object.

In almost all kinds of causes, there is a complication of circumstances.

Some circumstances are essential, others are superfluous.

Some are absolutely needed to the produce an effect. Others are only conjoined by accident.

When these superfluous circumstances are numerous, remarkable, and frequently conjoined with the essential, they have such an influence on the imagination.

Even in the absence of the essential circumstances, they:

• carry us on to the conception of the usual effect, and
• give to that conception a force and vivacity, which make it superior to the mere fictions of the fancy.

We may correct this propensity by a reflection on the nature of those circumstances.

But it is still certain, that habit takes the start and gives a bias to the imagination.

To illustrate this by a familiar instance, let us consider a man who is hung from a high tower in an iron cage.

He cannot refrain from trembling when he surveys the precipice below him, even if he knows he is perfectly secure from falling, by his experience of the iron’s solidity which supports him.

Though the ideas of fall, harm and death are derived solely from custom and experience.

The same habit:

• goes beyond the instances:
  • from which it is derived, and
  • to which it perfectly corresponds.
• influences his ideas of such objects as are in some respect resembling, but fall not precisely under the same rule.

Depth and descent strike so strongly on him.

Their influence cannot be destroyed by the contrary circumstances of support and solidity, which should give him a perfect security.

His imagination runs away with its object, and excites a passion proportioned to it.

That passion returns on the imagination and enlivens the idea.

This lively idea has a new influence on the passion.

It adds the force and violence of that passion.

His fancy and affections, mutually supporting each other, cause the whole to have a very great influence on him.

Why do we need to seek other instances, when philosophical probabilities offer us an obvious instance in the opposition between the judgment and imagination arising from these effects of custom?