A distinction is made between sensation and perception. The raw data before it is processed or transmitted to the brain is sense data. the processed data after it is processed by the brain is persense data (a term I coined). Persense data explains a lot about, for example, optical illusions, loss of night vision or unnoticed degradation of hearing.
Buddhism considers perception (pratyaksa) to be one of two (the other being inference) valid means of knowledge (pramāna). This is uncontroversial. What is to be minimally known is the physical reality. The question whether reality includes entities other than the physical ones.
If you had to start investigations into philosophy there are no better places to start than ontology and epistemology.
Two of the oldest “branches” of philosophical inquiry, it lays the foundation for the rest of your philosophy to come.
Ontology is the study of what exists. Epistemology is the study of what is known and how it is known.
These questions cannot sound simpler. Yet very few satisfactory and probable answers have been given.