"In keeping with this interpretation of history,

nineteenth-century European Orientalist scholarship tended to focus on what scholars saw as Islam's "classical" period, from its rise to the period in which it had supposedly reached its zenith and attained its purest form; everything thereafter was regarded as largely a story of decline and degeneration, or at least cultural and social rigidity and stasis. Moreover, a view of Islam as a coherent and distinctive civilization with an essentially unitary culture led many Orientalists to assume that the dominant ideas and institutions of all Muslim societies, and the ways in which Muslims behaved and interacted in all places and times, were at bottom expressions of Islam's unchanging cultural essence, its core values and ideas, which could best be understood by studying texts from its classical period. As a result Orientalist scholars tended to be less interested in the ways in which the thinking and behavior of Muslim communities varied from place to place or changed over time - that is, in the persistent diversity and complexity of Muslim belief and practice - or in what contemporary Muslims actually did and thought and how they lived.

In other words, the implicit or explicit premise of much of nineteenth-century Orientalist scholarship was that there was indeed a homo islamicus, a distinctive "Islamic man" with a more or less fixed mindset that was fundamentally different from, indeed absolutely opposed to, the mindset of "Western man." The essential characteristics of the members of this subspecies could be identified by the use of philological methods to study certain key texts which were regarded as embodying the core principles of Islamic civilization. The Qur'an was naturally deemed to rank first among these, followed by a relatively limited set of religious, moral, philosophical and legal writings generated by the learned elite before Islam's decline set in. Through the study of these key texts scholars believed that they could deduce the characteristics of "the Muslim mind," on the assumption that all Muslims, from the rise of Islam until the present, were constrained to think and believe and act within the rigid limits set by the essential character of the civilization to which they belonged. The upshot of the prevalence of this paradigm, and of the philological methods which underpinned it, was that, despite the enormous erudition of the best of the nineteenth-century Orientalist scholars and the very important contributions they made to scholarship on Islam, over time the field would become rather isolated and introverted, unwilling or unable to change in order to make better sense of a changing world and of new intellectual perspectives.

-Contending Visions of the Middle East: The History and Politics of Orientalism (The Contemporary Middle East) by Zachary Lockman, pp. 76-77

The thing that strikes me is how I think Muslims have also internalized/subscribe to this mentality as well!