Anything that has the ability to act independent of causality has a soul.
That is you!
When "God's Will", "Fate", "Karma" and other constructs of the deterministic simulation we live in hold no sway over you, when you have cast all of the inhibitions of reason, rationality, forethought, afterthought, intution, ideation and conscience, then in the pure spontaneousness of that moment, that action, you see/feel your soul. You know it's real.
All questions about soul are bound up in the necessary transformation of duality - where two become one.
The Freewill/Determinism debate illustrates this principle philosophically. But the intellect is properly a tool of investigation, not a yeilder of conclusions, and there is far too much circular argumentation on this topic.
In terms of metaphysics, souls are literal fields of etheric energy that permeate your physical being. You'll feel that quite often, feel your etheric field physically I mean - but will not be aware of it unless your consciousness is raised to par with the spiritual intelligence or force that permeates the physical world/Universe.
Anything that thinks, breathes, consumes, produces and changes (or mutates) has a spirit. This includes all organisms, some machines, and extra-dimensional or extra-planar beings/entities. Spirit establishes continuities by which souls traverse the many realms of existence. For a soul to enter, there must a spirit by which it can be carried. The analogy of soul as bird (or plane) and spirit as wind or air providing the currents for its flight works nicely. The word "current" is also electrical, remember, seaguing into the body (bio-electricity) and thus linking our concepts of "spirit" and/with the digital realm underlying the essential matrices of numbers, shapes and colours that support interactive existence.