This is an answer to a specific issue brought up in the comments on the theme of the OPs question. That is the nonsense that is the Derridian quote 'The Einsteinian constant is not a constant' in the context of Structuralism & Science. I'm putting it here as its obviously too long to go in a comment.
Derrida wrote Sign, Structure & Play in the Discourse of the Human Sciences to present at a symposium at John Hopkins University in Baltimore in 1966 titled The Language of Criticism & the Sciences of Man. The intention of the symposium was to clarify the field of structuralism and define some of its common problems across disciplines. One should not be misled by the 'Sciences of Man' to suppose that they were primarily interested in the hard sciences - they were not - but to sciences applied to man, that is the study of man in his own being, for example sociology, anthropology or literary criticism
After the oral presentation by Derrida of his paper, Hyppolite, a French philosopher, and translator of Hegel, in an attempt to understand Derridas 'centre for a structure' asked the following question:
With Einstein, for example, we see the end of a kind of privilege of empiric evidence. And in that connection, we see a constant appear, a constant which is a combination of space-time, which does not belong to any of the experimenters who live the experience, but which, in a way, dominates the whole construct; and this notion of the constant - is this the center?
Now Derridas essay, was not on Relativity, nor did it make any substantive scientific claims. It is primarily on the structural anthropology of Levi-Strauss although it touches on the thought of Foucault, Althusser & Lacan. So why does Hippolyte choose an example from the Physical Sciences to interrogate Derridas notion of the 'centre'? Putting this question aside, let us examine his.
His question admits a fairly straight-forward reading. Einstein famously did Gedankenexperiments, that is thought experiments rather than rely on empirical experiments in the tradition of empirical science; one can say here that there is a break with tradition, a break that continues with speculative forms of physics such as String Theory or Loop Quantum Gravity.
The 'constant' that he alludes to could be the speed of light, which was the speculative move of Einsteins that framed his entire theory. But this does not make sense, as Hippolyte says that this constant is a combination of spacetime. This points us in the direction of the spacetime metric on a four-dimensional manifold, an elegant reformulation of Einsteins theory of relativity by his friend Minkowski, and in this reformulation the metric is an invariant, that is a constant.
This already shows that Hippolyte is well-informed about about the structure of Einsteins theory in a broad-based way. But what can he mean by saying that it doesn't belong to any of the experimenters who live the experience? How can a metric belong to anyone? The spacetime metric is a mathematical fiction it belongs to no-one. Further we do not live and experience spacetime but live and experience space and time. These ideas are distinct - they would have to be, otherwise Minkowski wouldn't have had to invent spacetime.
Minkowski uses this metric to anchor his interpretation of Einsteins theory, which explains why Hippolyte says 'it, in a way, dominates the structure'.
The Einsteinian constant is not a constant, is not a center. It is the very concept of variability - it is, finally, the concept of the game. In other words, it is not the concept of something — of a center starting from which an observer could master the field — but the very concept of the game which, after all, I was trying to elaborate.
The first thing to note is that there is no such notion as an 'Einsteinian constant' in physics, but Derrida is not referring to any concepts in physics in a specific way, here he is using the qualifier 'Einsteinian' to name the constant that Hippolyte brings up in his question.
Now Derrida says that this constant 'is not a constant and not a centre'. What can this mean? It is this Derridean statement that has caused something of a ripple in science quarters.
It is this statement that is quoted in Sokals hoax paper, and in the book he cowrote with Bricmont - Fashionable Nonsense - they say it is the papers
first major gibberish quote, namely Derrida’s comment on relativity (“the Einsteinian constant is not a constant . . .”). We haven’t the slightest idea what this means— and neither, apparently, does Derrida
but they generously add
but as it is a one-shot abuse, committed orally at a conference, we shall not
belabor the point.
Weinberg in a reponse to his critics in the New York Times says:
[when] I first encountered this paragraph, I was bothered not so much by the obscurity of Derrida’s terms “center” and “game.” I was willing to suppose that these were terms of art, defined elsewhere by Derrida. What bothered me was his phrase “the Einsteinian constant,” which I had never met in my work as a physicist.
Well, we've shown that Einsteinian constant is just the name that Derrida has given to the constant in Hippolytes question. The real question is about the Derridean terms 'constant', 'centre' and 'play'. The wikipedia article referred to above has this to say about 'centre':
The "center" is that element of a structure which appears given or fixed, thereby anchoring the rest of the structure and allowing it to play. In the history of metaphysics specifically, this function is fulfilled by different terms (which Derrida says are always associated with presence): "eidos, archè, telos, energia, ousia (essence, existence, substance, subject) aletheia, transcendentality, consciousness, or conscience, God, man, and so forth." Whichever term is at the center of the structure, argues Derrida, the overall pattern remains similar. This central term ironically escapes structurality, the key feature of structuralism according to which all meaning is defined relationally, through other terms in the structure. From this perspective, the center is the most alien or estranged element in a structure: it comes from somewhere outside and remains absolute until a new center is substituted in a seemingly arbitrary fashion. "The center", therefore, "is not the center."
Roughly, the centre should organise or structure the whole, but looked at historically, different centres have been substituted,leaving the structure the same. But the structure, by the theory of structuralism, should determine the centre. It does not - hence it escapes structurality - (and hence Post-Structuralism). Thus 'the Einsteinian centre/constant is not a centre/constant'.
Essentially Derrida is saying that Hippolytes example drawn from the physical sciences is not a good example of his ideas, this is only to be expected as he Derridas paper is on the human sciences and not the physical or mathematical ones in this specific form.
This critique is echoed by Gabriel Stolzenberg , an American professor of mathematics, in an unpublished letter to the New York Times wrote:
A friend of mine was disposed to believe the charge about Derrida.
But when she looked at the text, and found that you are making this
Big Deal about an unclear answer to an unclear question at the end of
a talk that had -nothing- to do with physics, her reaction was (this
is not verbatim but it's faithful to the spirit of it), "That's it??
This is all they have on him??"
Finally, this lack of balance between your charge and your evidence
reminds me of a conversation between Alik Volpin and Vladimir Bukovsky,
two great Soviet dissidents, back in the USSR. Alik was talking about
the the importance of obeying the laws, to which Bukovsky replied, "But
doesn't the KGB always say, give us the man and we will find the charge?"
And similar sentiments were expressed by Michael Holquist (professor of comparative literature, Yale) & Robert Shulman (professor of molecular biology, Yale) in correspondance with the New York times that was published:
Alan Sokal’s hoax is rapidly ceasing to be funny. An enterprise that originally had all the marks of a good joke is beginning to bring out the worst in respondents.
I'll leave the final word to Plato, in Georgias he has Socrate say:
What’s this, Polus? You’re laughing? Is this yet another kind of refutation which has you laughing at ideas rather than proving them wrong?