From The Oxford English Dictionary (on-line subscription only:existence, n. abstract noun
The state of being existent.
†1. Actuality, reality. Obsolete.(Opposed to apparence: the French words often so occur in the Roman de la Rose.)
c1384 Chaucer Hous of Fame i. 266 Allas what harme dothe Apparence Whan hit is fals in existence.
c1400 Rom. Rose 5552 To se Hym that is freend in existence From hym that is by apparence.
1430 Lydgate tr. Hist. Troy i. v, A deceyte is couertly yment..As it were sothe in very existence.
2. a. Being; the fact or state of existing; ‘actual possession of being’ (Johnson). in existence: as predicate = ‘extant’.
1817 J. Mill Hist. Brit. India II. iv. ix. 298 It created some evils of the greatest magnitude which previously had no existence.
1856 B. Brodie Psychol. Inq. I. ii. 56 These facts sufficiently proved the existence of some actual disease.
1871 H. Alabaster Wheel of Law p. xxxvii, Buddhists..see more reason to lament existence than to be grateful for it. b. Continued being; continuance in being.
1874 J. R. Green Short Hist. Eng. People viii. 492 The colony was now firmly established and the struggle for mere existence was over.c. Continuance of being as a living creature; life. (Sometimes in disparaging sense: ‘a mere existence not worthy the name of life’.)
1860 Baroness Bunsen in A. J. C. Hare Life & Lett. Baroness Bunsen (1879) II. v. 276 His existence of bodily ease and freshness.
1870 Dickens Edwin Drood vii. 40 We have had a wretched existence.3. A mode or kind of existing.
1867 M. Arnold Empedocles on Etna i. ii, Other existences there are, that clash with ours.
1878 R. Browning La Saisiaz 28 New existence led by men and women new.4. concrete noun.
a. All that exists; the aggregate of being.
1868 ‘G. Eliot’ Spanish Gypsy i. 51 All beauteous existence rests, yet wakes.b. Something that exists; a being, an entity.
1846 J. S. Mill Syst. Logic i. iii. §1 An enumeration of Existences, as the basis of Logic, did not escape the attention of the schoolmen.
1891 C. R. Francis in Indian Mag. Sept. 459 There is no limit to the ever-increasing number of deified existences.
As an noun of concept, it is a mistake of language to say that “existence” is in anyway tangible. It exists as an attribute only.
You may find it helpful to think of “colour/color” that, although a noun, cannot exist independently as it is abstract, a concept.
In its use as a concrete noun (see 4 above) it is comparatively rare and indicates “all things apparent” or “a being.”
I hope this helps. I often find that people get into all manner of difficulties and compose strange questions when they do no phrase their questions properly.
One of the best examples of this is the parable of the computer in “The Hitchhiker’s Guide to the Galaxy” in which the people devise a big computer to answer “What is the answer to Life, The Universe and Everything?” and the answer comes back “42”https://www.youtube.com/watch?v=aboZctrHfK8
The moral behind this is “Be precise. Make sure the question is well formed.” I don't think yours was.