Is philosophical truth always necessary truth?

Question

p147 of Section "Two Kinds of Truth" in Big Questions by Solomon says:

Perhaps the statement "the Forms are most real" is defensible through pure thinking and without regard for whether the apparent facts of the world support it. Indeed, most philosophers would say straight out that the facts of ordinary experience (or, for that matter, the facts of extraordinary experience) may have very little to do with philosophical truth. But then are all philosophical truths necessary truths - the product of reasoning? Can reason deliver on such an enor- mous promise? Some philosophers have certainly thought so; others have denied it. But almost all of them (until fairly recently) thought that if there were an answer to any philosophical question (or any question of knowledge), it would have to be either an empirical truth based on experience or an a priori truth that was both necessary and a product of reason.

Does "philosophical truth" mean the answers to philosophical questions?

Does "the fact of ordinary experience (or, for that matter, the facts of extraordinary experience) may have very little to do with philosophical truth" mean that empirical truth has little to do with philosophical truth?

• If "yes" to my first question, does it mean that the answers to philosophical questions can't be empirical truth?
• To take it further, does it imply that the answers to philosophical questions have to be necessary truth?

In "almost all of them (until fairly recently) thought that if there were an answer to any philosophical question (or any question of knowledge), it would have to be either an empirical truth based on experience or an a priori truth that was both necessary and a product of reason",

• why is it "(until fairly recently) thought" instead of "think"? What do most of them think?

• If philosophical truth can't be empirical truth, why does it have to relax that to "either ... or ..."?

Thanks.

Answer 1

Philosophy covers two domains: physika (empirical truth: science) and meta ta physika (rational truth, metaphysics).

Philosophical answers can be on one or both of those groups (Thermodynamics is about mathematics and physics, so it is an empirical+metaphysical truth; set theory is a purely mathematical, ergo metaphysical truth; chemistry is mostly empirical truth).

In addition, some metaphysical truths are necessary (not all), for example Logic and Mathematics (which are not part of empirical knowledge, but they are metaphysical knowledge).

Important: most metaphysical truths have not necessarily a meaning (e.g. 1=1 is true, but has no meaning per se, other than a tautological one). Such kind of truth are like saying: "Eureka! This sentence is true!", which doesn't tell or mean nothing. Russell, among others, sustained that Logic is tautological, which is quite obvious and evident: any rule that validates logic is necessarily a logical rule. Ergo, metaphysical truth is not necessarily meaningful. Pure truth and falsehood are just different, but have no meaning per se. When metaphysical truth links with empirical truths (e.g. "fire burns"), then, there's a meaning: we want to know the truth, we don't want falsehood (e.g. we reject "fire does not burn" in favor of "fire burns", because truth, the second statement, allows survival).

Such fact is very interesting (my own speculation): days after being born, we probably find that truth is true ("Eureka! This is true!"), and we build all our judgements and knowledge around such fact (e.g. weeks later, the second judgement could mean something like "knowing is true" (notice the subject and the object have not been yet discovered), then, "seeing is true", "This (object) is true" (emergence of the object), "Me (subject) is true" (emergence of the subject), "Mom (object) is true", "Mom (object) is good (for subject) is true", "Mom is bad is false", etc.). Such is the placeholder to build all following logic, math, physics, etc. upon. Such would be be the beginning of our history. Truth is true could be the fundamental stone of knowledge, of reason, the paramount synthetic a priori truth. Repeat: just speculating.

Answer 2

Does "philosophical truth" mean the answers to philosophical questions?

Judging by the quoted passage that would seem so be what the authors mean.

Does "the fact of ordinary experience (or, for that matter, the facts of extraordinary experience) may have very little to do with philosophical truth" mean that empirical truth has little to do with philosophical truth?

Again, that would appear to be what the authors are saying. However, this would only be true on some rather limited accounts of what philosophy is about. Some philosophers in the analytical tradition, including Russell at one time, conceived philosophy as being nothing but conceptual analysis. On that basis, philosophy is an examination of concepts and is not directly empirical. Many other philosophers would disagree and allow that philosophy is about empirical matters and is not just an exercise in reasoning. David Hume's philosophy, for example, is substantially an exercise in naturalism.

Does it mean that the answers to philosophical questions can't be empirical truth?

They can definitely be informed by empirical truth. One might for example appeal to empirical data from psychology to inform our understanding of freedom of action.

Does it imply that the answers to philosophical questions have to be necessary truth?

It is a good idea not to conflate what is necessarily true with what is a priori knowable. Some approaches to philosophy are presented as a priori exercises in pure reasoning that aim at discovery of necessary truths. Kant would be an obvious example. But plenty of other philosophers are not so ambitious, especially those in the empiricist tradition.

Why is it "(until fairly recently) thought" instead of "think"? Why does it have to relax that to "either ... or ..."?

Historically, a fairly popular dichotomy is that between what is a priori knowable and what is empirically knowable. The distinction has been criticised by many philosophers in the last century, and some have even rejected the idea of a priori knowledge altogether. It remains a point of contention among philosophers.