Voluntarism is the metaphysical and epistemological view that regards the will as superior to the intellect and to emotion, and that will is the basic factor, both in the universe and in human conduct. The term was introduced by the German sociologist Ferdinand Tönnies (1855 - 1936), and its etymology is from the Latin "voluntas" (meaning the will or desire).

It is usually contrasted with Intellectualism in both its metaphysical and epistemological forms. It is distinct from the concept of Voluntaryism (the doctrine in Philosophy of Life that association among people should only be by mutual consent, and that everything that is invasive and coercive, including Government, is evil and ought to be abandoned).

In Metaphysics, Voluntarism is the theory that God or the ultimate nature of reality is to be conceived as some form of will.

In its earliest formulation by the Medieval Scottish philosopher John Duns Scotus, Voluntarism is the philosophical emphasis on the divine will and human freedom in all philosophical issues. According to Scotus, it is the will which determines which objects are good, and the will itself is indetermined (not determined by anything else). Medieval Voluntarism was also championed by the Jewish philosopher Avicebron (1021 - 1058) and William of Ockham.

19th Century Voluntarism has its origins in Immanuel Kant, particularly his doctrine of the "primacy of the practical over the pure reason". He argues that, intellectually, humans are incapable of knowing ultimate reality, but this need not (and, Kant argues, must not) interfere with the duty of acting as though the spiritual character of this reality were certain.

Following Kant, two distinct lines of Voluntarism proceeded:

• Rational Voluntarism was originated by Gottlieb Fichte, who argued that the world and all its activity is only to be understood as material for the activity of the practical reason, which is the means through which the will achieves complete freedom and complete moral realization.
• Irrational Voluntarism was developed by Arthur Schopenhauer, who believed that the will is an irrational, unconscious urge, in relation to which the intellect represents a secondary phenomenon. He asserted that all activity is blind insofar as the individual agent is concerned, although the power and existence of the will are continually asserted.

In Epistemology, Voluntarism is the view that belief is a matter of the will rather than one of simply registering one's cognitive attitude or degree of psychological certainty with respect to a stated proposition. Thus, it is possible to simultaneously feel very certain about a particular proposition, and yet assign it a very low subjective probability.