Plato seems to have been more an icon and an inspiration than an authentic source for Islamic philosophers. So far as is known, the only works available to them in Arabic translation were the Laws, the Sophist, the Timaeus and the Republic. His name was often invoked as a sage and an exemplar of that wisdom available to humankind among the Greeks before the revelation of the Qur'an. This in itself could represent a kind of affront to orthodox Islam, which tended to view the human situation before the Qur'an's 'coming down' as one of pervasive ignorance (jahaliyya). However, the rise of humanist culture in Baghdad during the ninth and tenth centuries ad, which involved Syriac Christian translators, presupposed a gradual acceptance of Greek wisdom in which Plato figured paradigmatically, even though far fewer of his works were made available in translation than those of Aristotle.
Plato's influence on Islamic philosophy can be observed most clearly in ethics and political philosophy, given the works available to Islamic thinkers. However, his role lay more in creating an environment hospitable to philosophical reflection than in contributing to the formation of specific philosophical doctrines (where the influence of Aristotle was stronger) (see Aristotelianism in Islamic philosophy). He was referred to as 'the sublime and divine Plato', no doubt because his writings seemed to lead one more directly than any other Greek philosopher to reflect on human actions in the light of transcendent goals. At this level of inspiration, collections of sayings attributed to Plato, notably on the adverse relation of knowledge to wealth and power, helped to set a stage on which philosophy could play a propaedeutic role for Muslims seeking truth as they followed the 'straight path' laid out in the Qur'an. At the same time 'philosophy' so practised could present itself as an encompassing way of life, so competing with observant Islam. Here a discussion inspired by Plato regarding the relative weight of logic and grammar is relevant, since Arabic had tended to legislate semantic conflicts by recourse to grammar, while Greek philosophical texts (themselves originating in another language) extolled logic as a norm for rational discourse, transcending the peculiarities of a single tongue and the grammar proper to it. This potential conflict came to the fore in considering the qualities required for a just ruler of a Muslim polity, specifically regarding the relative merits of 'prophecy' (the generic Islamic term for the deliverances of revelation) and philosophical reason.
The locus classicus for such considerations is Plato's Republic, which offered an ideal paradigm for a just ruler that was adopted in lieu of Aristotle's more legislative treatment in the Politics - the only text of Aristotle's not translated into Arabic. Al-Farabi's treatise on the 'perfect state' (al-Madina al-fadila (The Virtuous City)) presents a didactic Neoplatonic version of Plato's Republic, one in which 'the Good' is transmuted into 'the First' in such manner that the ordering proper to cosmos and the microcosmic ideal polity emanates from the ever-fruitful One (see al-Farabi §§2, 4). Al-Farabi states unequivocally that philosophical reason outstrips prophecy as a requisite for the wise and just ruler, but the pattern established in his treatise was able to be adapted by those who weighed their relative merits otherwise. What was severely contested, however, was the relevance of Plato's ideal scenario (or its adaptation by al-Farabi) to the actual ruling of an Islamic polity. Rulers themselves took issue with it, speaking from experience, as did intellectuals (such as al-'Amiri) who assimilated Plato's lofty philosophical ideals to Sufi ascetic practices. For such as these, Plato's dictum that philosophers are prevented from attaining wisdom by the mores of the city in which they live spoke more directly to their experience.
Plato's teaching on the human soul as 'an incorporeal substance that moves the body' seemed to offer a philosophical teaching conducive to Islam, even though Ibn Sina's way of adopting this teaching would put 'philosophy' in conflict with Qur'anic faith in resurrection of the body (see Ibn Sina §6; al-Ghazali §3). Ethical thinkers like Ibn Miskawayh adopted Plato's tripartite division of the soul, however, in elaborating an ethical teaching relating Islam to a wider humanist culture, relying on extant sayings which quoted Plato: 'whoever rules his reason is called wise; whoever rules his anger is called courageous; and whoever rules his passion is called temperate.' The influence of sayings of this sort would permit a wise ruler like Ibn al-'Amid to say that he considered himself a 'member of the following [shi'a] of Plato, Socrates and Aristotle'. In this manner, Plato contributed an anthropology to Islamic thought which could be used to elaborate the 'straight path' of the Qur'an as well as bring it into contact with a wider humanist civilization.
See also: Aristotelianism in Islamic philosophy; al-Farabi; Greek philosophy: impact on Islamic philosophy; Neoplatonism; Plato; Platonism, Early and MiddleDAVID BURRELL