There is an “illness” science has called Synaesthesia, where there is a tendency for the senses to intermingle. Early focus was on extreme cases that hampered a persons ability to function. But there are subtler forms of it that are actually advantageous.
Artists have been documented who “see” music as colours. Others “hear” visual movement or patterns. BBC has an article about some of the recent studies of this. You have probably heard of the ‘music of the spheres’, a remarkable experience some people have where they experience their environment as a symphony of sound, literally hearing the vibration of becoming. The name comes from the music of the solar system that can similarly be perceived.
To understand this experience, yogis of old speak of how the sense originate as one, differentiating as the fundamental elements arise. In the field of consciousness, there is an observer-observed relationship. As being becomes, it differentiates into fundamentals, the base elements on the observed side and the corresponding senses on the observer side. Those 5 base or subtle elements, recognized in both early western science and the east, form the groups of the chemical elements or atoms. (recent changes to the traditional groupings of elements obscures the five-fold nature)
Because the senses are different aspects of the same fundamental thing – attention – in the right circumstances they can cross over. Smell and taste are more basically developed in humans and thus more closely linked. It is not unusual for those senses to blend. But the other senses can as easily cross-perceive. Indeed there are people who can fully perceive an object with just one sense connection. With just attention on a object, all of its characteristics can be known and perceived. People who meditate on objects like a candle may step into such an experience.
This illustrates the doorway to another form of experience some use the word cognition for. Cognition in this context is complete knowledge of something. In a short experience, it is like a download of everything about the perceived. If we, for example, cognize an apple, a simple look would not only tell us what the apple looks like, but we would be able to, in memory, review the experience and perceive the taste of the uneaten apple, it’s core, its parent tree, its life cycle, even the whole history of the species. All of that is available within anything. It is made of intelligence, from intelligence, and perceived by intelligence. When we know intelligence, we come to know all aspects of it.
Never underestimate the value of attention.