For Heidegger, the objects, or the non-human entities, with which Dasein comes face to face in its world do not have the same way of Being. The Being of such objects and things is either ready-to-hand or present-at-hand, according to Heidegger.
For Heidegger, ready-to-hand and present-at-hand, in their characterizing of and referring to objects, things, or entities in Dasein’s world, do not speak about or signify different classes of things. Ready-to-hand and present-at-hand refer to two different ways in which Dasein encounters, experiences, and relates to non-human entities in its world.
According to Heidegger, Dasein’s own relating to a certain object, either practically or theoretically and detachedly, is what determines if this specific object is encountered as ready-to-hand or present-at-hand.
Dasein calls the things that it sees as having a practical function and a useful purpose or use “equipment”, and experiences and relates to them as ready-to-hand entities. This relating to entities as ready-to-hand, or as equipment, is a fundamental way of Dasein’s being-in-the-world, according to Heidegger. Heidegger calls this practical turning toward things “concern”. In Being and Time, Heidegger says that nature, in its entirety, offers itself to Dasein as ready-to-hand.
The sun, whose light and warmth are in everyday use, has its own places – sunrise, midday, sunset, midnight … Here we have something which is ready-to-hand … The house has its sunny side and its shady side; the way it is divided up into “rooms” is orientated towards these.
Martin Heidegger, Being and Time
In contrast to this practical experiencing of things, present-at-hand is Dasein’s non-practical, disinterested, detached, and objective turning toward things; a turning, or an experiencing, in which objects and things appear to Dasein as having no practical use.
For instance, science, or the scientific-objective turning toward entities, regards entities as present-at-hand, for it studies, examines, and observes their constitution and physical properties.
An object, or a thing, is never constantly and forever only either present-at-hand or ready-to-hand, but rather both, becoming ready-to-hand in the hands of a certain Dasein and present-at-hand in the hands of another Dasein, for an object’s way of being depends on how Dasein relates to it, experiences it, and encounters it. In other words, the same object, or the same entity, can be present-at-hand or ready-to-hand, depending on how Dasein treats it.
In Being and Time, Heidegger says that what determines any object’s way of being is Dasein itself; that is, how Dasein encounters and relates to this specific object. For instance, rocks can be both present-at-hand and ready-to-hand. They are generally and usually present-at-hand, but they are ready-to-hand for the Dasein that uses them and cuts and prepares with them.
A ready-to-hand object becomes present-at-hand when it stops carrying out the function for which it was originally put together, when it becomes useless, or when it is found in the hands of someone who does not know how to use it or what it is for.
Broken or unusable objects are experienced as “unready-to-hand”. This “unreadiness-to-hand” is Dasein’s experiencing of broken and unusable objects as present-at-hand, according to Heidegger.
Conversely, broken, useless, neutral, or unusable objects, that is, present-at-hand or unready-to-hand objects, become ready-to-hand in the hands of a certain Dasein that succeeds in putting them to a particular practical purpose.
For more articles on Heidegger‘s philosophy, visit this webpage.