You don’t have to have read a lot of Buddhist texts to know that consciousness comes streaming through six doors, each one framed by one of six cognizing organs and opening onto one of six cognized objects. Just take a moment to explore the field of experience, and you will see that you know things in six different ways. One sphere of knowing is visual, another is auditory. Seeing and hearing are two different activities, each using separate parts of the body and distinct processing centers in the brain. If you cycle between one and the other, you will know quite directly what is happening right now in the environment around you. Moment after moment you will see and then hear, hear and then see, some specific input of data flowing through these two sense doors.
The same is happening with the knowing of smells, tastes, and tactile sensations. Each involves a different mode of consciousness, and each translates some aspect of the environment into a different experiential language. Consciousness is singular in the sense that it is all just knowing, but this knowing manifests variously as particular organs respond to particular objects. In classical Buddhist thought these variations are called the five strands of sense experience (kāma-guna), and they appear to the mindful meditator as a stream of changing experience.
Here is the thing: These five sense inputs can only access information that is happening in the present moment. They are each connected to specialized receptors at the end of nerve bundles, which are responding to real-time stimuli with present moment representation. You cannot hear a bell that has not yet rung, nor directly experience a touch that took place years ago. When we appear to do this, by remembering past experience or by imagining future experience, we are using the sixth mode of consciousness, the mind door. When a mental object (which covers a wide territory of memories, thoughts, plans, computations, and so much more) is known by the mind, a moment of mental consciousness occurs. We generally call this “thinking,” but in the broadest sense of the word.
Mental experience is similar to sense experience in so far as it, too, is happening in the present moment. But an important difference is that the content of a mental experience may go well beyond the present moment to represent something far into the past or future. The thought you are having right now is of something you did yesterday or anticipate doing tomorrow. It does not work the same way for the other senses. You can form a mental image of something that happened in the past, and that mental image might even draw upon some of the brain’s visual apparatus as you appear to “see” it in your “mind’s eye,” but you do not see it in the same way you see an object before you in the present moment.
This ability to think about the past and the future yields tremendous learning, planning, and problem-solving skills, but it also comes with at least one major drawback. It is possible for people to dwell almost exclusively in the mental mode and have very little direct contact with the senses. Yes, one might check in with the other senses enough to navigate the physical world, but often as little as necessary to keep one’s bearings and provide basic input for the mind’s proliferations. As the human animal lives less in a rapidly changing natural environment filled with sensual nuance and permeated with danger, and more in a synthetic world with all its parameters defined, it becomes more adaptive to rely heavily on the mental realm at the expense of the senses.
But for many people this becomes a trap. What happens when you can’t stop spinning out threatening alternative futures, or you cannot help reliving past traumas? What happens when the pendulum swinging from past to future becomes a fiendish carnival ride you can neither slow down nor escape? At a certain point one can feel driven by the mind’s habit of churning over various scenarios, and this often results in a great deal of suffering.
The solution offered by the Buddhist tradition is systematic training in attending to the senses. The first foundation of mindfulness, for example, guides the meditator exclusively to the body door. Become aware of physical sensations—whether those associated with breathing, walking, or almost any other activity—and when the mind adverts toward thinking, as it will surely do often, simply re-direct awareness back to bodily sensations. It sounds simple enough, yet it has a huge impact.
The reason this is effective is that the mind can be aware of only one thing at a time. If it is a thought, then there is no sense cognition; but in a moment of sense cognition, there are no thoughts. At first, there may be far more mind moments of mental cognition than of sense cognition in the stream of consciousness; but over time, as the practice develops, one can actually have multiple consecutive moments of sense awareness uninterrupted by “thinking about” what one is sensing. To those who habitually think too much, this is experienced as blissful relief. And it is an essential starting point for growth in understanding.
The Buddha offers an image of the mind like a water jug. If it is half-full of water, Mara can gain access and cause all sorts of mischief. This happens when one senses the world with half of one’s available awareness, and thinks about it with the other half. Mara, a trickster figure, represents the unseen (i.e. unconscious) neurotic habitual tendencies that usually direct mental chatter. But if the water jug is full to the brim, Mara can gain no access. Conscious awareness is fully engaged, but with direct sense experience rather than with mental narrative. By filling up the senses, one empties out the mind. With the peace that ensues from quieting the mind in this way, dharma investigation can begin.