# Did Descartes believe arguments for Euclid’s parallel postulate were cogent?

Contents

## Why was the parallel postulate controversial?

Controversy. Because it is so non-elegant, mathematicians for centuries have been trying to prove it. Many great thinkers such as Aristotle attempted to use non-rigorous geometrical proofs to prove it, but they always used the postulate itself in the proving.

## Who proved the parallel postulate?

Ibn al-Haytham

Ibn al-Haytham (Alhazen) (965-1039), an Arab mathematician, made an attempt at proving the parallel postulate using a proof by contradiction, in the course of which he introduced the concept of motion and transformation into geometry.

## What is the significance of Euclid’s parallel postulate?

It states that through any given point not on a line there passes exactly one line parallel to that line in the same plane. Unlike Euclid’s other four postulates, it never seemed entirely self-evident, as attested by efforts to prove it through the centuries.

## Why was mathematics important to thinking of Descartes?

According to the present interpretation, Descartes relies upon mathematical reasoning to explicate the concept of infinity, which is essentially mathematical.

## What is the negation of Euclidean parallel postulate?

2 The Hyperbolic Parallel Postulate is equivalent to the negation of the Euclidean Parallel Postulate.

## How do we know that the Euclidean parallel postulate is independent of other axioms?

We have seen that the Euclidean parallel postulate is independent of the incidence axioms by exhibiting three-point and five-point models of incidence geometry that are not Euclidean.

## Does Euclid’s fifth postulate imply existence of parallel lines?

Yes. Euclid’s fifth postulate imply the existence of the parallel lines. According to Euclid’s fifth postulate when a line x falls on a line y and z such that ∠1+ ∠2< 180°. Then, line y and line z on producing further will meet in the side of ∠1 arid ∠2 which is less than 180°.

## What are the consequences of the parallel postulate?

One consequence of the Euclidean Parallel Postulate is the well- known fact that the sum of the interior angles of a triangle in Euclidean geometry is constant whatever the shape of the triangle. 2.2. 1 Theorem. In Euclidean geometry the sum of the interior angles of any triangle is always 180°.

## What are Euclid’s postulates?

Euclid’s postulates were : Postulate 1 : A straight line may be drawn from any one point to any other point. Postulate 2 :A terminated line can be produced indefinitely. Postulate 3 : A circle can be drawn with any centre and any radius. Postulate 4 : All right angles are equal to one another.

## What is another name for the parallel postulate?

The parallel postulate is equivalent to the equidistance postulate, Playfair’s axiom, Proclus’ axiom, the triangle postulate, and the Pythagorean theorem. There is also a single parallel axiom in Hilbert’s axioms which is equivalent to Euclid’s parallel postulate.