Personal religious beliefs can significantly influence one's interpretation of empirical evidence, often acting as a lens through which individuals view and understand the world. These beliefs can shape the questions considered worth asking, the methods deemed appropriate for investigation, and the interpretation of results. For instance, someone with strong religious convictions might interpret archaeological or historical evidence in a way that aligns with their religious narratives. In scientific fields, such as biology or cosmology, individuals may interpret findings in a manner consistent with their beliefs about creation and the origin of life. This influence is not inherently negative; it reflects the diverse perspectives individuals bring to their understanding of the world. However, it underscores the importance of recognising and critically examining these biases to ensure a balanced and objective approach to empirical evidence.

Religious belief systems address contradictions between faith-based knowledge and scientific evidence in various ways, depending on the tradition and the nature of the contradiction. Some systems adopt a literal interpretation of religious texts and may reject scientific findings that contradict these texts. Others may interpret their religious doctrines metaphorically or symbolically, allowing for a reconciliation with scientific evidence. For example, the Catholic Church's acceptance of the theory of evolution demonstrates a way in which religious belief systems can integrate scientific discoveries without abandoning core religious tenets. Additionally, some religious thinkers propose the concept of non-overlapping magisteria (NOMA), which suggests that science and religion address different kinds of existential questions and thus can coexist without conflict. This approach allows for faith-based knowledge to coexist with scientific evidence by maintaining that each addresses different aspects of human experience and understanding.

Faith is often associated with belief in the absence of empirical evidence or in conjunction with evidence that is not fully verifiable. It is deeply personal and subjective, relying on trust and conviction. Unlike reason, which is based on logic and rational thought, or sense perception, which relies on observable phenomena, faith often deals with the unobservable and the transcendent. It is similar to emotion in that it is a personal and internal experience, but it is distinct in its focus on spiritual or religious beliefs. Faith can also intersect with other ways of knowing, such as when ethical or moral beliefs (influenced by faith) guide one's reasoning process or when religious texts are interpreted using reason. In TOK, faith is recognised as a powerful, albeit subjective, way of knowing that contributes to the diversity of perspectives and understandings in the pursuit of knowledge.

Religious experiences, by their nature, are challenging to study or verify empirically because they are deeply personal, subjective, and often transcendental. Empirical methods, which rely on observation, measurement, and repeatability, are not well-suited to capture the essence of experiences that are often described as beyond the ordinary and not universally accessible. However, some aspects of religious experiences can be studied indirectly. For example, neuroscience can explore the brain's activity during reported religious experiences, and psychology can study the impact of these experiences on individuals' behaviour and mental states. Yet, these studies do not confirm the spiritual validity or truth of the experiences; they only provide a physical or psychological perspective. The subjective nature of religious experiences means that they remain largely within the realm of personal testimony and interpretation, which falls outside the scope of empirical verification.

Different religious traditions justify the use of faith over empirical evidence by emphasizing the limitations of human perception and understanding. For instance, in many Eastern religions, such as Hinduism and Buddhism, there is a belief that ultimate reality transcends what can be perceived and understood through the senses and rational thought. These traditions often argue that empirical evidence only captures the superficial aspects of reality, while faith can provide a deeper, more holistic understanding. In Abrahamic religions like Christianity, Islam, and Judaism, faith is often seen as a gift from God, a means to comprehend divine truths that are beyond human reasoning. The belief is that faith encompasses trust in the divine and provides a pathway to understanding spiritual truths that empirical evidence cannot reach. These traditions hold that faith is not irrational but is a different kind of rationality that operates on a spiritual level, where empirical evidence has limited applicability.