Summary: The Philosophy of No

Philosophy of science generally falls into two opposite excesses: either it is too philosophical, i.e. focuses too much on general principles, the a priori and rational values, or it is too scientific, in other words confines itself to particular results, the a posteriori and experimental values.

A new philosophy of science is needed, one that shows under what conditions general principles can lead to particular results, and vice versa.

We must succeed in conciling empiricism and rationalism: Empiricism needs to be understood; rationalism needs to be applied ¹. Or: We prove the value of an empirical law by making it the basis of a reasoning. One legitimates a reasoning by making it the basis of an experiment ².

This is not dualism in the sense that empiricism and rationalism are not opposed but complement each other.

Applied rationalism takes the lessons provided by reality and translates them into a programme for realisation. This is why Bachelard defines the scientific rationalism he calls for as the epistemological current according to which application is not a defeat, a compromise. It wants to apply itself. If it applies itself badly, it modifies itself. It does not therefore deny its principles, it dialecticizes them ³.

As a result, this type of rationalism is distinguished from others by its open character:

It is the only philosophy that applies itself by determining an overcoming of its principles. In short, it is the only open philosophy. All other philosophy posits its principles as intangible, its first truths as total and completed. All other philosophy takes glory in its closure ⁴.

The true philosophy of knowledge is therefore an open philosophy, which seeks in reality what contradicts previous knowledge; whereas, in general, philosophers tend rather to consider what contradicts their theories as details, or signs of the irrationality of the given, and do not modify their thesis in any way.

Bachelard then clarifies the meaning he gives to the "Philosophy of No", which gives the work its name: it should be understood that the new experience says no to the old experience, without which obviously it is not a new experience ⁵.

The philosophy of no is the privileged epistemological doctrine that makes it possible to think about and accompany scientific progress. Progress occurs when experiments are organised whose purpose is to contradict, or invalidate previous experiments, and thereby to call into question hitherto accepted theories.

An experiment that merely confirms previous experiments and theories may be useful; but it is not thanks to it that the march of science will be able to make a qualitative leap forward.

It is therefore a question of trying to organise experiments in order to disprove or criticise the theories hitherto accepted; it is this approach that precipitates scientific progress. The philosophy of no, is not, contrary to what its name might suggest, a closed philosophy:

This no is never definitive for a mind that knows how to dialectise its principles ⁶.

This is not the "no" of nihilism; on the contrary, it is a constructive activity, designed to think about and consolidate the fertile nature of experimentation.

Bachelard makes a twofold request: to philosophers, he asks for the right to use philosophical concepts detached from the systems in which they originated (for example: to use the Kantian category without being Kantian). To scientists, he asks them to admit that their work is guided by metaphysical presuppositions (e.g. on the nature of matter, etc.).

Bachelard finds himself dreaming: against philosophers who tend to want to apprehend reality from a single overhanging and all-encompassing point of view, there should be a philosophy for each problem, each equation: there should be a philosophy of epistemological detail.

¹ La Philosophie du non, PUF, Quadrige, Paris, 1994 avant-propos, p.5
² ibid.
³ ibid., p.7
⁴ ibid.
⁵ p.9
⁶ ibid.,p.10