The universe is observable, so at least some part of truth must be scientific.
Although Alan of Lille came long before the scientific approach was formalized by Francis Bacon, almost 400 years in fact, the same theme can be found in Alan's writings that governed Bacon's approach. Essentially, since the mind is able to perceive reality, and since the mind can be trained to make true observations and reasonable conclusions, Alan concluded that the universe could be largely understood by reason alone, given that the person was being honest and disciplined. Later, this idea would grow through the early university system to produce the scientific approach that has governed the progress of man since its inception.
God has given us more faculties than reason alone.
Remember that the University in Paris in the 12th century still fell within the earliest era of the University, one largely religious in nature. Here is a beautiful demonstration of that early religious approach to life and experience—Alan argues that there seem to be at least two different modes for the way a person comes to understand reality: the scientific mode (although he wouldn't have used that word since he was so historically early), and the religious mode, which he called faith. Faith seems to be better suited to the purposes of human life concerning divinity, experience and meaning.
Something can be known about religion through reasoning.
In an ironic twist, Alan decides to decode the sacred geometry of the Creed, for the purposes of demonstrating the application of reasoning to the abstract concepts of religion. What he determines is that religion is a systematic idea following central professions, or axioms. But for experiencing the inherent religious truths of the Creed, Alan believed faith must be employed.
Mathematics is a true assessment of the universe.
Alan was a huge fan of the mathematician Pythagorus whose works influenced the structure of Alan's arguments, and Alan employs many geometrical principles in his work. This could be seen as an early form of analytic philosophy.
