Rav Yaakov Kaminetsky was once travelling from Israel back to the United States, accompanied by his son and granddaughter. Sitting next to Rav Kaminetsky was one of the heads of the Histadrut, the Israeli labour federation. The two discussed many different issues. Throughout their long discussion Rav Kaminetsky’s son and granddaughter periodically came to ask Rav Kaminetsky if there was anything he needed.
Rav Kaminetsky’s companion was amazed, and told Rav Kaminetsky how he himself was not particularly close with his grandchildren, and would never expect such behaviour from his children. He asked him what Rav Yaakov’s secret was, and how it is that his children and grandchildren were so respectful. Rav Kaminetsky told him that for people who believe in Darwin’s theory of evolution, every successive generation is more developed and advanced than the previous one. In such a culture, why would the young honour the old? But in my tradition, said Rav Kaminetsky, each older generation is closer to Mount Sinai and our becoming a people. My children and grandchildren look up to me, because I am one link closer to the source.
The 13th principle of Maimonides is the following.
I believe with perfect faith that the dead will be brought back to life when
G-d wills it to happen.
In a CNN article titled Winehouse burial raises Jewish questions about tattoos, cremation, a member of the Reform movement opined about cremation, "physical resurrection isn't something that progressive Jews believe in, so that isn't a concern," he said.
..."In fact, he argued, there is Biblical precedent for cremation."
..."If you go back to Biblical times, it is normal and there are references to King Saul being cremated," he said.
The verses in Samuel 1: 12 and 13 state, "they burned them there. Then they took their bones and buried them..." The Stone edition of the Tannach explains, "according to most commentators, they burned Saul's belongings. ...Radak suggests that the bodies had become decomposed and infested so the people burned the flesh, leaving the bones for burial."
As far as the belief in physical resurrection goes, I guess people feel that they are more enlightened and more intelligent than the Rambam, the brilliant court physician who authored many scholarly works.