The Probability of Causes

There are 3 Origins of Chances: Experience, Contrariety, Analogy

I explain the probability of chances to explain the probability of causes.

All the probabilities of causes are derived from the association of ideas to a present impression.

Habit:

• produces the association
• arises from the frequent conjunction of objects.

The habit must:

• arrive at its perfection by degrees, and
• acquire new force from each instance that we experience.
  • The first instance has little or no force.
  • The second makes some force added to it.
  • The third becomes still more sensible.

Our judgment arrives at a full assurance by these slow steps.

This gradation from probabilities to proofs is usually insensible.

The difference between these kinds of evidence is more easily perceived in the remote differences than in those near and contiguous.

Imperfect Experience as a Kind of Probability and an Origin of Chance

1. Our first experience of anything happens before any proof can exist.

No one refers to his first experiences of anything all the time.

But learned people have experienced many events.

• They have been able to connect causes and effects.

When we see something once to follow from any object, we conclude that it will always follow from it.

But we do not believe this maxim because we frequently meet contrary experiences, not because we have few experiences.

These contrary experiences lead us to the second kind of probability.

The Contrariety of Causes as a Kind of Probability and an Origin of Chance

2. The second kind of probability is the one where we reason with knowledge and reflection from a contrariety of past experiments.

Our lives would be very happy if:

• the same experiences were always conjoined together, and
• there were no uncertainty in nature

This uncertainty causes our reasoning to consider the contrariety of events because:

• one observation is frequently contrary to another, and
• causes and effects do not follow in the same order as we had experienced.

What is the nature and causes of contrariety?*

Philosophers observe every part of nature.

• They see so many principles hidden by minuteness or remoteness.
• They find that the contrariety of outcomes can come from the secret operation of contrary causes, not from any contingency in the cause.

This possibility is converted into certainty by further observation.

They see that:

• a contrariety of effects always betrays a contrariety of causes
• this contrariety comes from their mutual hindrance and opposition

A peasant sees the stopping of a clock.

• The only reason that he can give is to say that there is something wrong.
• But a craftsman knows that the clock’s spring always acts on the clock’s gears.
• He thinks that the spring had failed because of dust.

Likewise, philosophers form a maxim that:

• the connection between all causes and effects is equally necessary, and
• its seeming uncertainty in some experiences comes from the secret opposition of contrary causes.