Concepts we keep and concepts we toss out

Often when we think about philosophical concepts like identity, existence, possibility, and so on, we find ourselves confronted with numerous apparent paradoxes that require us to revise our initial intuitive conception. Sometimes, however, the revisions necessary to render the concept coherent end up looking so extreme as to make us prefer to just throw out the concept altogether.

An example: claims about identity are implicit in much of our reasoning (“I was thinking about this in the morning” implicitly presumes an identity between myself now and the person resembling me in my apartment this morning). But when we analyze our intuitive conception of identity, we find numerous incoherencies (e.g. through Sorites-style paradoxes in which objects retain their identity through arbitrarily small transformations, but then end up changing their identity upon the conjunction of these transformations anyway).

When faced with these incoherencies, we have a few options: first of all, we can decide to “toss out” the concept of identity (i.e. determine that the concept is too fundamentally paradoxical to be saved), or we can decide to keep it. If we keep it, then we are forced to bite some bullets (e.g. by revising the concept away from our intuitions to a more coherent neighboring concept, or by accepting the incoherencies).

In addition, keeping the concept does not mean thinking that the concept actually successfully applies to anything. For instance, one might keep the concept of free will (in that they have a well-defined personal conception of it), while denying that free will exists. This is the difference between saying “People don’t have free will, and that has consequences X, Y, and Z” and saying “I think that contradictions are so deeply embedded in the concept of free will that it’s fundamentally unsavable, and henceforth I’m not going to reason in terms of it.” I often hop back and forth between these positions, but I think they are really quite different.

One final way to describe this distinction: When faced with a statement like “X exists,” we have three choices: We can say that the statement is true, that it is false, or that it is not a proposition. This third category is what we would say about statements like “Arghleschmargle” or “Colorless green ideas sleep furiously”. While they are sentences that we can speak, they just aren’t the types of things that could be true or false. To throw out the concept of existence is to say that a statement like “X exists” is neither true nor false, and to keep it is to treat it as having a truth value.

I have a clear sense for any given concept whether or not I think it’s better to keep or toss out, and I imagine that others can do the same.  Here’s a table of some common philosophical concepts and my personal response to each:

Keep
Causality
Existence
Justification
Free will
Time
Consciousness
Randomness
Meaning (of life)
Should (ethical)
Essences
Representation / Intentionality

Toss Out
Knowledge
Identity
Possibility
Objects
Forms
Purposes (in the teleological sense)
Beauty

Many of these I’m not sure about, and I imagine I could have my mind easily changed (e.g. identity, possibility, intentionality). Some I’ve even recently changed my mind about (causality, existence). And others I feel quite confident about (e.g. knowledge, randomness, justification).

I’m curious about how others’ would respond… What philosophical concepts do you lean towards keeping, and which concepts do you lean towards tossing out?