Psychological enquiry, while scientific in nature, faces several limitations that affect its measurements and conclusions.

First, there is a lack of absolute zero point in psychological measurement. Unlike physical sciences where measurements have a clear zero reference, psychological measures do not have an absolute zero, making comparisons relative rather than absolute.

Second, psychological tools have a relative nature. Tests and measurements used in psychology are developed within specific cultural and contextual frameworks, which limits their universal applicability and standardisation across different populations.

Third, there is the problem of subjective interpretation of qualitative data. When psychologists collect qualitative data through interviews, observations, or case studies, the analysis and interpretation of such data involves subjectivity, which may affect the objectivity of findings.

Additionally, psychological enquiry must address ethical considerations. Researchers must follow ethical principles including voluntary participation of subjects, obtaining their informed consent, and sharing of results with the participants. These ethical requirements, while necessary, also pose certain constraints on how research is conducted.

It must be understood that quantitative and qualitative methods are not contradictory; rather, they are complementary to each other. A suitable combination of both methods is warranted to understand a phenomenon in its totality.