Contemporary neuroethics necessitates consideration and appreciation of an underlying natural philosophy, that grounds neuroscience (and its constituent disciplines) and the humanities. Toward this, a number of operational definitions are introductory to an explanation of neuroethics...
1: the inherent character or basic constitution of a person or thing 2: a controlling force in the universe or the sum of such forces in an individual 3: a kind or class usually distinguished by fundamental or essential characteristics
1: a discipline comprising as its tasks: metaphysics, logic, epistemology, ethics, engaged in study or pursuit of field/practice 2: a search for a general understanding by chiefly speculative rather than observational means
Science: an area of knowledge that is an object of study, particularly as concerning general laws; usually as obtained through specific rational methods
Ethics: a system of beliefs, attitudes and practices reflective of a metaphysical appreciation engaged in moral decision making; a ‘binding’ set of beliefs and faith in such beliefs
Neural/Neuro: pertaining to or derived from the structure, function (or concept) of nerves, and/or nervous systems, such as brains.
From this, we can consider two viable definitions of "neuroethics":
1) Inquiry and investigation into the neural basis of moral thought, intention and behavior
2) Inquiry and investigation into the moral, ethical and policy-related issues arising in, and from neuroscientific research and its clinical applications
Both of these definitions involve a solid foundation of the facts of neural function, the realities of science, medical practice, and social impact, and from this (a.) recognize the exigencies and issues that are inherent and arise, (b.) the moral obligations and responsibilities involved with these issues, and (c.) how various ethical systems may be utilized to address and resolve these issues, questions and problems. This allows us to construct a normative and applied neuroethics "...from the ground up", as schematically illustrated below.
We can think of this being analogous to an egg: the "living content" is on the inside, while the "shell" that provides shape, structure and support is on the outside. These are not mutually exclusive; without the "living content" (epistemic capital, facts and realities of nature, focus and telos of neurophilosophy and neuroscience, etc., that give rise to the moral obligation and ethical enactment of responsibilities), the "shell" (guidelines and policies for research, clinical applications, social practices, etc.) would be "hollow", and would crumble. Likewise, without the structure and support provided by the "shell" of (well conceived, realistic and prudent) guidelines and policies, the "living content" (of epistemic capital, science) would be without shape, and could not meaningfully develop or be applied in practice(s).