People have often misunderstood what I have said about Einstein, so here is a brief clarification.
So, there is circumstantial evidence that Einstein had seen the 1904 papers of Poincare and Lorentz. So why should we believe Einstein?
It was in this context that I pointed out that it was not as if Einstein was a person of such high moral character that he never told a lie.
My point was NOT that Einstein had one or more children out of wedlock. I do not regard that as immoral, and I specifically stated that "Children are not illegitimate, though parents or the social order may be."
My point was that Einstein lied lifelong about his first "illegitimate" child Lieserl. He never saw her face. He did this cruel and unpardonable thing to his own child, just so that society should think well of him.
My point was that a man who could do this could tell a hundred lies about what papers he had read or not read.
Should we give Einstein benefit of doubt? It is strange that the story of the greatest scientific genius of all time can be defended only on grounds of this principle of criminal law. But benefit of doubt does not apply: that is a principle of criminal law meant to save living human beings from judicial mistakes. In history we must do justice.
This point about Einstein's character was only meant for laypersons. For people with some knowledge, I have a much stronger point from Einstein's mistake, given below (and in the excerpts).
Stephen Hawking says that "Einstein invented general relativity single handed". Even this is incorrect.
The equations of general relativity were first obtained by David Hilbert, the greatest mathematician of the time after Poincare. However, Hilbert made the mistake of sending the equations in a letter to Einstein. At that time Einstein was lecturing and using the wrong equations. Quickly, within 5 days after receiving Hilbert's letter, Einstein claimed to have "independently rediscovered" the very same equations of general relativity!
Einstein did not solve the equations either. The three famous tests of relativity used the solution obtained by Schwarzschild.
In fact, Einstein had a poor grasp of the mathematics of 4-dimensional geometry. He asked his friend Marcel Grossman to help him.
So, all the work in general relativity too was also done by others, Einstein single-handedly got the credit!
As a former patent clerk, Einstein's real expertise was in the art of grabbing social credit!
Why do people continue to believe a story contrary to all facts? Because people reisist change. How? They accumulate hypotheses to "save the story". It is a "theorem" of the philosophy of science that any story, howsoever fantastic and contrary to fact, can be saved for any length of time by accumulating sufficiently many hypotheses.
Hilbert's gullibility is a classic case in the point. Hilbert quickly understood Einstein's ignorance. He stated, "Every boy in the streets of Gottingen knows more about 4-dimensional geometry than Einstein". He understood that Einstein was also utterly ignorant about the philosophy of time and space.
Hilbert asked the obvious question: how could this ignorant man have come up with such a profound theory as special relativity?
However, Hilbert found a clever answer. He opined that it was just because of his ignorance that Einstein could be so original!
"Do you know why Einstein said the most original and profound things about space and time in our generation? Because he learned nothing at all about the philosophy and mathematics of time and space."
If an acute person like Hilbert, a Western thinker of the first rank, could be so gullible and fall prey to the phenomenon of "saving the story", what can one expect from lesser mortals?
Kip Thorne says (about special relativity) "Lorentz, Poincare waffled". Thorne is partly right. Lorentz did "waffle". He believed in the Heaviside-Lorentz contraction, he believed in "local time", he believed in "aether".
But this is what Poincare said in his 1904 paper.
"From all these results...would arise an entirely new mechanics, which would be, above all, characterized by this fact, that no velocity could surpass that of light1, any more than any temperature can fall below absolute zero. [Original footnote: 1. Because bodies would oppose an increasing inertia to the causes which would tend to accelerate their motion; and this inertia would become infinite when one approached the velocity of light.]" [Emphasis mine]
Poincare compared the speed of light to absolute zero---a conceptually impassable barrier. The rest of relativity follows (and Poincare derived and so named the Lorentz transform in 1905).
Some waffling this!
Poincare's 1905 paper (the mathematical one, not the English translation of the 1904 paper) too appeared in print before Einstein submitted his paper. That would have given Einstein some 3 weeks instead of the 5 weeks in which he claimed to have invented special relativity.
Pais in his biography of Einstein claims that Poincare needed an additional hypothesis. This is pure bunkum. Pais aims at the gullible who do not check things out. He wants to help them to "save the story". The dead giveaway is that Pais misquotes and misrepresents Poincare, who is far more lucid and thorough than Einstein.
The Indian Nyaya Sutra recognizes such misrepresentations of the opponent's position as one of the 22 sure ways of losing the argument.
First a small point in support of Whittaker.
Whittaker had said that before 1904 Poincare used the term "principle of relative motion", and shifted to "principle of relativity" only in 1904. This is a bit subtle, and I looked for more matches.
I found "longitudinal mass". Lorentz uses it in quotation marks, because it is obviously such a strange notion. Einstein boldly used it just like that---as if it were long-established terminology! Later he said he had not seen the paper by Lorentz.
My major point comes from my "epistemic test". As a teacher I often have had to check whether a student has cheated. A good way to do this is to test the student's understanding of what he claims to have authored. Lack of understanding is proof of copying, and conceptual mistakes are proof of lack of understanding. Later I applied this test systematically to claims of "independent rediscovery" in history.
Einstein's special relativity paper was titled "On the electrodynamics of moving bodies". But Einstein considered just one moving body, while Poincare thought also of the two body problem. Later in life Einstein tried to solve the many body problem (in general relativity). Where Poincare had immediately understood the mathematical implications, here is the mathematical mistake Einstein made, even thirty years later. (The reference to Einstein is hidden under the rubric "many other authors" whose papers are cited along with Einstein's in the endnote.)
On my "epistemic test", Einstein's conceptual mistake is proof that he copied from Poincare.
Here is how I later solved the two body problem of electrodynamics. The paper also clarifies a confusing point due to which physicists remained unclear in the matter for so long.
Another way to understand Einstein's mistake is that he did not fully reject "aether". The word "aether" has two meanings: (1) as an absolute reference frame and (2) as a device to provide "contact" between distant bodies. Poincare rejected aether in both senses, Einstein only in the first sense.
Today most people go by the authority of science, not by personal knowledge or any "scientific method". This is just the same as yesterday when they went by the authority of religion. Therefore the make similar blunders.
"Thus, the new standard of truth is this: if it is published by an important person in a respectable journal it must be true or, at any rate, very likely true...The most pathetic example of this standard of truth is the grievous mathematical error3 in a paper published by Einstein4 in the Annals of Mathematics, in 1938, on the relativistic many-body problem, which exposes his fundamental lack of understanding of the special theory of relativity relative to Poincaré.
"...As a clerk in the patent office, Einstein understood the subtler legalities of this process: that one may copy ideas if one does not copy the expression verbatim. A more recent example of this sort is Bill Gates, one of the richest men of all time, who legally won the claim of having innovated the windowing software that, despite its bugs, bears a striking resemblance to the earlier software of Apple Macintosh. The relative unimportance of the creative process is emphasized by the fact that no one has heard of the person who initially thought up the point-and-click concept behind the windowing software."
 H. Poincaré, The Value of Science . Eng. Trans. by G.B. Halstead, 1913. Reprinted, Dover 1958, p. 104.
 C. K. Raju, Time: Towards a Consistent Theory, Kluwer Academic, Dordrecht, 1994, p. 122.
 C. K. Raju, The Eleven Pictures of Time, Sage, 2003.
 C. K. Raju, "Relativity: History and History Dependence", talk at at "On Time" conference, Liverpool, British Society for History of Science, and Royal Society for History of Science, 1999. See Abstract, Extended Abstract, Excerpts from Presentation. More in The Eleven Pictures of Time, chp.
(for the technically informed)
1. Einstein's mistake was to try to approximate functional differential equations by ordinary differential equations. Why this is a mistake is explained in this excerpt from Time: Towards a Consistent Theory (Kluwer Academic, Dordrecht), chp. 5b. The full paper is here.
2. What quantitative difference does it make to physics? This is explained in this 2004 article which calculated and compared the solutions of both types of equations. See abstract and highlighted portion in excerpt. The full paper is here.
3. Acceptance speech for Telesio-Galilei Award 2010 (for pointing out Einstein's mistake).