"I learned this, at least, by my experiment; that if one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours." (Thoreau, in Walden)
The practice of advancing confidently is only hampered by doubt, yet doubt arises from fear, and fear is an essential emotion of the human body. Fear is one of the first emotions experienced in life, a genetically encoded response to threatening situations; an emotion that through evolution greatly enhances survival. In fear, a fight or flight response occurs without meditation by consciousness, driven by hormones signaling other molecules to activate in a complex cascade of physiological response to protecting life. Extinguishing the fear response would be detrimental to any species, including our own. It's a valuable response for individual and species survival.
Yet, our rapidly evolving culture moves too fast for the biological processes to be modified in a way that balances this fear response with the shifting environment. In birth and separation from the mother, we form a distinct view of being a separate 'self'; a view that is defined by our physical being, that which is defined through the repetitive, automatic breath of life. In this awareness of our physical form as distinct from others arises a connection to it, an attachment and desire for its continuance, and a fear of its loss upon death.
The fear of death thus drives the attachment to life, to memories of past and future, to avoid the present because in the present, the attachment to life disappears. When present, fear is not tangible because there is only the moment of being present, there is no future or past, thus no concept of end; it is an infinite pause which fleetingly disappears. In this glimpse of the moment, all doubt dissipates and the confident advancement in life occurs.
Hence, cultivating these glimpses of presence, repetitively with practice, yields a profound reduction in doubt and fear. And in that infinite pause, a joy arises, some call it bliss, some call it God, some call it self-transcendence, some call it peace, some call it love, some call it awareness, some call it spirituality.
Like the Indian proverb of the elephant and the eight blind men, what one experiences defines the description. So, as Thoreau notes "I learned this, at least, by my experiment"....it's all in the individual experimentation. Our genetics, our human physiology, our neurobiology creates an organism in which experimentation is possible, practice coming to the present moment and noting what happens, as one naturalist of the mind encourages.