Some sections of the Torah do explicitly
say they were written by Moses (e.g., Deuteronomy 31:22: "Moses therefore
wrote this song the same day, and taught it the children of Israel"). That
might be taken as odd, if he wrote the whole thing.
Also, the entire story of Moses is narrated
from third-person omniscient perspective, treating him just like the rest of
the characters. That too suggests that Moses was not the author. Take for
example the verse: Now the man Moses was very meek, above all the men which
were upon the face of the earth (Numbers 12:3). (Also, by definition, if he was
the meekest man in the world, he wouldn't have written that – he would have
been too modest.) And then Moses died
The rabbis of the Talmudic era did believe
that, divinely inspired, Moses wrote the Torah himself - up to the last eight
verses. The Talmud preserves a rabbinical dispute about whether Moses wrote
those last verses describing Moses death, burial and legacy - or whether they
were written by his successor, Joshua (tractate Bava Batra, 14b-15a).
Come the Middle Ages, the rabbis noticed
more difficulties. Rabbi Abraham Ibn Ezra wrote in his 12th-century Bible
commentary that 12 verses in the Torah are anachronistic and seem to indicate
that they were written after the time of Moses. For example, when Moses was
alive, the Canaanites still controlled the Holy Land. So the verse ending with
And the Canaanite was then in the land (Genesis 12:6) ostensibly could not have
been written by Moses, but by someone who lived after the Israelites took over
Canaan, that is, after Moses died.
In his commentary on this verse, Ibn Ezra wrote, It holds a secret of which the wise man should be silent (he doesn't tell us what the secret is, but it may be that Moses seems not to have written all of the Torah).
Enter Spinoza
Indeed scholars remained silent on the
topic for centuries, until in the 17th century, Baruch Spinoza read Ibn Ezras
commentary – and could remain silent no more. In his Theological-Political
Treatise (1670), Spinoza elaborated on the topic and concluded that Moses could
not possibly have written the entire Pentateuch. His English contemporary
Thomas Hobbes came to the same conclusions, without Ibn Ezra's help.
A century later, a French professor of
medicine named Jean Astruc set out to prove the two heretics wrong, using the
newly- emerging science of textual criticism. With the help of techniques that
had, up to then, been applied only to Latin and Greek classics, he studied the
Torah and came to the conclusion that Moses compiled the Book of Genesis by
putting together two older texts. He published these findings anonymously in
1753.
Using similar techniques, in 1805 Wilhelm
Martin Leberecht de Wette, a German Bible scholar, published a study arguing
that Deuteronomy had been written by a different author or authors from the
rest of the Torah.
Half a century later, in 1853, Hermann
Hupfeld, an Oriental studies scholar, showed that what Astruc identified as two
sources was apparently three.
All
these studies were consolidated towards the end of the 19th century by Julius
Wellhausen, another German biblical scholar.