Orthodox and Conservative Jews hold that the prophecy of Moses is held to be true; he is held to be the chief of all prophets, even of those who came before and after him. This belief was expressed by Maimonides, who wrote that "Moses was superior to all prophets, whether they preceded him or arose afterwards. Moses attained the highest possible human level. He perceived God to a degree surpassing every human that ever existed... God spoke to all other prophets through an intermediary. Moses alone did not need this; this is what the Torah means when God says, "Mouth to mouth, I will speak to him". The great Jewish philosopher Philo understands this type of prophecy to be an extraordinarily high level of philosophical understanding, which had been reached by Moses and which enabled him to write the Torah through his own rational deduction of natural law. Maimonides, in his Commentary to the Mishna (preface to chapter "Chelek", Tractate Sanhedrin), and in his Mishneh Torah, (in the Laws of the foundations of the Torah, ch. 7), describes a similar concept of prophecy, since a voice that did not originate from a body cannot exist, the understanding of Moses was based on his lofty philosophical understandings.