Having spent his first years of adult life in the war, Joseph returned determined to make a better life for his soldiers and their like. More Macmillanite than Macmillan during his first term of office, he was committed to state welfare, and what a critic called "architectural determinism". Over time, however, he came to feel pangs of disillusionment with Butskellism.
The first doubts were in 1969/70. In a series of speeches, later reprinted in the Times, Joseph questioned the staples of Butskellism as he and his colleagues had practised them. Through these he gained a reputation for radicalism. Harold Wilson and the media misattributed the inspiration for these lectures to a one-day meeting of the shadow cabinet at the Selsdon Park Hotel; my own crucial part in their drafting escaped notice at the time.
Once ensconced back in office in 1970, Joseph returned to his old ways: a good man fallen among civil servants. His second period of rebellion coincided with his government's election defeat in February 1974.
This came about incidentally, because when Edward Heath set up his shadow cabinet at the end of 1974, he denied Joseph the shadow chancellorship - wary, perhaps, of his ideological adventures four years previously. Joseph was piqued and declined another portfolio. To avoid media speculation, it was agreed that Joseph would sit in the shadow cabinet without portfolio; and Heath also proposed that Joseph set up a small "think-tank" with the aim of persuading workers and unions that they would be better off if they emulated the moderation of their European confreres. By this means, Heath hoped to keep Joseph quiet.
Chance had it that a few weeks previously Joseph had invited me, as a Middle-Eastern specialist, to his Chelsea home to brief him on Arab-Israeli relations. Our chat ineluctably spilled over into domestic politics. As a result, he later in- vited me to discuss setting up a new institution, which was to become the Centre for Policy Studies.
His idea was to make a few critical speeches in order to raise money from disaffected captains of industry to fund the institution. I wrote a highly critical obituary of Heath's reign, which, a few weeks later, became Joseph's "Upminster speech" - the first in a contentious series. Once again he was seduced by the widespread response to his radicalism, and revelled in it.
His admission that "we were wrong" struck a chord far beyond the Tory right. An intended retreat to keep him out of mischief became the launch-pad for Thatcherism.
We said little new, only stating the obvious: the attempt to stimulate the economy by state expenditure and credit creation, while trying to offset the inflationary effects by interest-rate manipulation and wage-price controls, was bound to fail. In Monetarism is not enough, a far-ranging critique of the dead-end reached by post-war economics, Joseph's rejection of "political geometry" - the compulsive search for the middle ground between parties, ignoring public perceptions - was matched by his criticisms of the Friedmanites as "inverted neo-Keynesians". His thesis was accepted by Margaret Thatcher (though never internalised into policy) and marked the high point of Joseph-Thatcherism.
His advance towards leadership of the Tory party stumbled in October 1974 with his much misquoted Edgbaston speech about the growth of the single-parent family and problem children. Today it reads as both prophetic and compassionate - only last week, I discussed with him the idea of republishing it with an epilogue.
His real fault at the time, he recognised, was to have flinched in the face of attacks from the yellow press, red bishops and lily-livered Conservatives. The five bulging sacks of supportive mail the speech drew confirmed that had he fought back, he would have swept the board. Instead, his withdrawal into apologetic silence left the Tories fearful for another two decades of confronting the decline in family life and rise of unmarried motherhood.
Joseph learned from the incident that he lacked an essential qualification for leadership - robustness. So having undermined Heath's position, he bowed out and left the way open for Mrs Thatcher, whom he had made deputy chairman of the Centre for Policy Studies.
On her election as Tory leader in 1976, a grateful Thatcher gave Joseph responsibility in the shadow cabinet for policy, third in order of precedence. However, he simply did not possess the inexhaustible reserves of will required to fight the party bureaucracy and his colleagues in order to move from a critique of Butskellism to an analysis of modern society, doctrines and policies for turning round the Tories and reshaping Britain.
He continued to preach his gospel courageously in the universities and polytechnics. But he left the initiative in the hands of Christopher Patten, then director of the Conservative Research Department, and the apparat, who served Jim Prior and fought tenaciously to preserve the old religion.
As a result, during this period in opposition, the opportunity to move forward from speeches to policy was lost. So the Thatcher government took office in 1979 with a better idea of what it was against than what it was for.
Joseph, a lion in opposition, was tamed by government: events took command and ideas were downgraded in the name of pragmatism, which originally meant judging ideas by their results but came to mean ignoring them. Thatcherism lost its ascendancy; the rest is history.
Even so, things can never be quite the same again. The Tories, dubbed the stupid party, showed that they could pick up ideas and run with them, and even win votes with them. In due course, Joseph's ideas and techniques will be studied and emulated - not necessarily by Tories. With belief in Socialism, Butskellism and now Thatcherism at an all-time low, the political jackpot awaiting the innovator who can strike a chord with a new ism, or at least a refurbished one, grows with time.
Sir Alfred Sherman was co-founder of the Centre for Policy Studies with Keith Joseph in the spring of 1974.