The answer to Could a sentient machine suffer? suggests that

The ability to suffer would not seem to be a necessary condition for sentience

This made me wonder what the minimum necessary and sufficient conditions for something to be considered sentient are?. The 'something' here does not necessarily have to be human or animal; I'm interested in the abstract notion here.

A little more formally:

Given an X. What are the necessary and sufficient conditions for X to acquire sentience?

  • I'm trying to avoid the moral problems when the question is formulated as in At what point can a being be said to have gained sentience?
    – dorzey
    Commented Aug 27, 2011 at 23:45
  • The problem is effectively about definitions at this point as several of the answers below suggest. Is there any way I could persuade you to reformulate to specify this a bit further? Perhaps something along the lines of "which if any philosophers have offered specific criteria for sentience?" This is also clearly close to the linked question -- maybe you could explain a bit further what "moral" problems you think you are avoiding in your formulation?
    – Joseph Weissman
    Commented Aug 31, 2011 at 17:19

3 Answers 3


Although this will seem at first glance to be a bold statement, the answer to these questions is actually remarkably simple: it's all in how you define sentience. That is, the necessary and sufficient conditions for sentience would be precisely as they are defined. I think what people really want to know—in fact what they might have meant to ask in the first place—is "how would one measure X in another entity?", X being sentience, consciousness, whether it can actually feel pain/love/happiness/sadness, etc. That's where the real challenge lies. This touches on ideas like Solipsism, Searle's Chinese Room Argument, and the mind-body problem in general. But when you are asking for the conditions which make X, you are simply asking for the definition of X; i.e. that which makes X distinct from everything else.

In this case, the necessary and sufficient conditions for sentience are (depending on how you define "sentient"):

Sentience is the ability to feel, perceive or be conscious, or to have subjective experiences.


Conscious or aware; Experiencing sensation or feeling.


Having sense perception; conscious; experiencing sensation or feeling.

–The Free Dictionary

  1. having the power of perception by the senses; conscious.
  2. characterized by sensation and consciousness.


  • Whilst the definitions are useful it raises the question as to what they actually mean. Are they not subjective? What does it mean to feel or perceive? What constitutes a sensation? Whilst it might be truly impossible to state totally objective criteria, I would be interested to learn if anybody has attempted it.
    – dorzey
    Commented Aug 29, 2011 at 10:19
  • 1
    Those are interesting questions indeed and I understand what you are getting at, but I would be careful how you word the questions though, in order to avoid ambiguity. Your write: "What does it mean to feel or perceive? What constitutes a sensation?" and again here you are asking for meanings/definitions. You bring up the idea of subjectivity, but the definition of something is different than the phenomenological experience of it. :)
    – stoicfury
    Commented Sep 1, 2011 at 18:36

Obviously, the question here is one of definition; how one defines sentience.

You quote an answer on an earlier thread, where someone wrote:

The ability to suffer would not seem to be a necessary condition for sentience

From a Buddhist perspective, this is exactly wrong; in Buddhist philosophy, sentience is defined as "the ability to suffer" (which is identical to "capable of sensation.")


Sentience can not be aquired like a possession. It is an attribute that is either there or is absent.

To be considered sentient there are several things that are required:

  • Must be able to learn from experience and make decisions based on them. (Learning)
  • Must be able to predict a result of an action soley from experience with the percieved envorinment (Decision Making)
  • Must be able to alter conditions in order to set up a result of an action (planning)
  • Must do be able all of the above with out direction or influence of any other being (Autonomy)

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