The notion of causality is depreciated in modern thinking. Bertrand Russell, in a paper that is the starting point for contemporary reflections on the problem, affirms that "The law of causality, […], like much that passes muster among philosophers, is a relic of a bygone age, surviving, like the monarchy, only because it is erroneously supposed to do no harm"[1].

Hume in fact dealt a decisive blow to the concept of cause, liberating it from its tie with necessity. Causality, the logical tie between cause and effect, is not demonstrable, and the relation between cause and effect can be observed exclusively on the level of experience, there where usage proves to us that a determined effect always follows a certain cause.

Even so, we can attribute to him the basis for the notion of cause to which Lacan refers when, in "Position of the Unconscious", he says that only the insistence of the unconscious allows us to "grasp the cause on the level from which someone like Hume attempts to flush it out"[2].

The Freudian concept on which Lacan bases the notion of cause that he proposes here is Nachträglichkeit, the effect of retroaction where a heterogeneous element that Freud defines as traumatic only becomes active when it subsequently takes on meaning for the subject.

In other words, for Freud, as for Hume, the cause remains exterior to the logical and discursive level, and that's what gives it its consistency as real. At the same time, the cause, considered as real, and therefore outside of meaning, only becomes effective when it gains meaning in the subjective dimension.

Here appears a conceptualization of the cause that does not coincide at all with the concept of cause employed in the scientific discourse.

When, in the neurosciences, we look for a molecule responsible for a behavior – instilling in public opinion an idea of concreteness and efficiency since we know where a molecule is and what it does –, the underlying concept of causality is the one common to the scientific discourse, which is an extensive concept.

The extension is defined by the fact of being partes extra partes, parts separated from one another. The extent is pure exteriority, with neither consciousness, nor thought, or anything to animate it. In fact, physics – the discipline that specifically studies this exteriority (what occupies this exteriority) – is a science of inert bodies, subjected to the fundamental law of energy according to which a body, in the absence of a net external force, is either at rest or if it is in motion, it moves with constant velocity and it will only stop if it encounters an object exterior to it.

When the neurosciences, with all their undeniable progress, research the brain to find the cause of a behavior, they inevitably fall back to researching an external cause (that the brain is located in the cranium changes nothing with regard to the definition of partes extra partes).

Inversely, if we ask where the heterogeneous or traumatic element is situated, the one that is activated after the fact by means of the mechanism of Nachträglichkeit, the only answer we can give is that it is not localized, that it has no spatial coordinates, that it is a placeless encounter, and a « bad encounter ». Not only does this contingent encounter have no meeting-place, it simply cannot be referred to any spatial coordinate. It is a pulsation; an unraveling of existence where time has stopped.

The cause, in psychoanalysis, as the cause of desire, has no extensive character; it is not situated on the exterior, because it is in the Other. The subject draws from the Other the cause of its own desire, and when that is not the case, when the voice or the gaze is not situated in the Other – which is no place in space – things are more difficult, which is why they take on the form of delusions or hallucinations.

Lacan played with this idea in one of his last conferences. If freedom consists in having within oneself ones' own cause, according to the classic Aristotelian definition that runs, in diverse formulations, throughout all of philosophy (to have in oneself one's own cause is different from being "causa sui", prerogative that Spinoza left to substance, the only one he called God), then, the psychotic is by definition the free man.

Lacan's last teachings jeopardize the structural distinctions of clinical categories, removing the limits that clearly separated neurosis and psychosis. Madness extended to the impossibility of affronting sexuality by means of knowledge, of logos and of reason concerns all speaking beings without any categorical distinctions.

Sexuality, where psychoanalysis finds its own real, different from the extensive one of science, is a field where the tie of cause and effect is broken. In "Position of the unconscious", Lacan thought of the cause in reference to a "reason": cause perpetuates the reason that subordinates the subject to the effects of the signifier. With the generalization of madness to all speaking beings, this reason is withdrawn, as though we were no longer even talking about the signifier to which the subject is subordinated.

The suspended time of the heterogeneous element finds no reason to latch on to; it drifts, circumscribed when it's possible by a sinthome.

This suspended, reasonless moment is the hic Rhodus hic salta of our clinic where the wager is to make a reason out of a sinthome, not to live by, but to live with (complement of means).