QuestionsShould we believe without proof?The heart knows first principles
Should we believe without proof?Faith goes beyond

The heart knows first principles

Blaise Pascal 1623 · 1662The heart has its reasons which reason knows nothing of.
See profile
What it claims

Reason is not our only source of knowledge: the heart is another.

Why

We know first principles (space, time, numbers) as firmly as proofs without being able to prove them: another route, the heart.

In short

"The heart knows first principles" is an argument by Blaise Pascal (Pensées, B282) on the question "Should we believe without proof?" (answer: faith goes beyond). Its claim: Reason is not our only source of knowledge: the heart is another. According to AskPhilosophy's logic check (Z3 solver), the argument is valid only if one grants a premise the author leaves unstated (P3). AskPhilosophy presents 1 objection, 1 of them with a documented reply, and the original text behind each premise, checked word for word.

Pensées, B282
Valid with an implicit premise

Against those who will believe only what reason demonstrates, Pascal shows that reason itself rests on principles it does not demonstrate.

P1First principles (there is space, time, motion, number) are not obtained by reasoning.
P2Yet we know these principles, as firmly as what we demonstrate.
P3 · implicit premiseWhat we know without demonstrating it, we know by another way than reasoning: Pascal calls it the heart.
Therefore reason is not our only source of knowledge: the heart is another.

click a premise to reject it

If you accept every premise, logic forces you to accept the conclusion. So the debate is about the premises.
Checked by a logic solver: the premises cannot all be true while the conclusion is false.
Without the implicit premise: Without P3, the computer finds a case where undemonstrated principles are known without any other faculty being involved: the conclusion does not follow.
P1 and P2 show there is undemonstrated knowledge; P3 is needed to conclude that it comes from another faculty. Critics mostly question the word "know": is a firm feeling really knowledge?
Analogy. A mathematician proves everything from axioms but does not prove the axioms. If he still holds them true, he knows them some other way: that "other way" is what Pascal calls the heart.

Objections

1

Each objection is a conversation: click to see who replies and where the debate stands.

The sceptics (Pyrrhonists), as Pascal presents them attacks premise 2

We do not know where we come from: perhaps we are made to be deceived. Feeling a principle strongly does not prove it true.

Pascal replies
Pascal
No one can truly doubt everything: nature confounds the sceptics, just as reason confounds those who claim to prove everything.