Let's filter this common sense by solving this quandary in simple steps.
Things have their identity in virtue of their function. As Shakespeare puts it: "A rose by any other name would smell as sweet" (Shakespeare, 1597). Glass is used for taking an amount of liquid, be it water or wine. Glass can come in any shape or be called by varied signifiers/names in different languages, its identity always lies in its function which is universal (Giddens, 1984, p. 23).
Truth; that is, verification of all material items in the world lies in their function. So, truth does exist in the materialist sense identified in its specific functions (Habermas, 1981, p. 78).
Then what about so-called "ideal truths" like honesty, love, hatred et cetera?
Basically, it needs to be understood that without material or materialisation the idea does not exist separately. Ideas always come from the material. How? There are two arguments. a) Brain is matter and ideas come out of neuronic processes (Ollman, 1976, p.45). b) If someone says "laptop", an image of a laptop appears in the listener's/reader's mind; however, if someone names something, one has never heard then one's brain fails to create an image of the object. So, one is unable to imagine an unobserved object (Bauman, 1989, p. 67).
Then how do people invent new things? Scientists? Fiction?
Coleridge terms it the secondary imagination. One has seen a dog and a horse, both available to primary imagination, then components from primary imagination can be taken to form secondary imagination as used by scientists and artists. Suppose, one can imagine a dog with a horse-head or vice versa since both are observed objects stored in primary imagination. The root always comes from material reality (Coleridge, 1817).
Humans in different languages have different names for the same material realities that exist. For example, the word "love" in English or "amor" in Spanish or a variety of signifiers in different languages denote the same materialisation of human behaviour. There's nothing like an ideal truth! Truth exists only in material form and language uses signifiers to denote that truth therefore the truth of every idea, thesis, argument or signifier of a signifier can be traced back to its material reality identified in function.
Therefore forms and names may change and deceive but the truth is always found in function (Ollman, 1991, p.23).
Truth is also dialectical in the sense it is not fixed and isolated; it changes in relation to others. The shirt you wear today can be verified as a shirt; But the truth is not isolated in space and time, since this is also the truth that this very shirt was a piece of clothing, cotton and seed and maybe it will be litter once thrown away. The truth is dialectical and the identity of the material lies in its function. Truth has a history and is not fixed, it changes in relation to other things and therefore must be understood as a process and a relation (Ollman, 1993, p. 45). As Ollman (1976, p. 45) states, understanding the dialectical nature of truth is crucial in grasping its ever-changing nature and the way it relates to other systems. This requires a relational analysis, as Foucault (1980, p. 45) suggests, and an understanding of its developmental history, as Bauman (1989, p. 67) states, in order to fully understand the truth of a material object or idea. Ultimately, the truth of any object or idea can be traced back to its material reality and its function in the world, as Giddens (1984, p. 23) suggests, and this understanding is crucial in seeing through the veil of common sense and ruling ideologies.
Source:
1. Bauman, Zygmunt. Modernity and Ambivalence. Polity Press, 1989.
2. Bourdieu, Pierre. Outline of a Theory of Practice. Cambridge University Press, 1977.
3. Coleridge, Samuel Taylor. "Biographia Literaria." 1817.
4. Foucault, Michel. Power/Knowledge: Selected Interviews and Other Writings, 1972-1977. Pantheon Books, 1980.
5. Giddens, Anthony. The Constitution of Society: Outline of the Theory of Structuration. University of California Press, 1984.
6. Habermas, Jürgen. The Theory of Communicative Action. Vol. 1: Reason and the Rationalization of Society. Beacon Press, 1981.
7. Ollman, Bertell. Alienation: Marx's Conception of Man in Capitalist Society. Cambridge University Press, 1976.
8. Ollman, Bertell. Dialectical Investigations. Routledge, 1991.
9. Ollman, Bertell. "Market socialism or socialization of the market?" Rethinking Marxism, vol. 6, no. 1, 1993, pp. 1-18.
10. Shakespeare, William. Romeo and Juliet. 1597.