Something is subjective if it’s mind-dependent in the sense that it exists only in someone’s mind, like a mental state (figment, dream, preference, belief, …). Something is objective if it’s not subjective, that is, if it’s mind-independent in the same sense. Something is objectively true, for example, if it’s true not merely in someone’s mind but independently of what people think, wish, and so on.

Is there objective truth? Rather than cite examples, I will first point out the self-defeating nature of believing that there isn’t. Consider the proposition (S) that there is no objective truth. Is that true or false, and is it objectively or subjectively so? Let’s look at the options. First, if S is objectively true, then there is objective truth after all, namely S, and S is therefore objectively false. Second, if S is subjectively true or false, that is, if it or its denial is just someone’s opinion, then it doesn’t preclude the existence of objective truth, just like my opinion that the sky is a certain color doesn’t preclude the sky’s being blue. If S is subjectively true or false in the sense that it or its denial is never more than an opinion in anyone’s mind, then it’s objectively true that S is subjective and S is therefore objectively false again. Third and finally, if S is objectively false, then, well, it’s objectively false—no problem.

To summarize, our options with regard to S are ultimately twofold: we must either affirm that S is objectively false, in which case there is objective truth (S‘s denial, for instance), or admit we can’t speak to the issue. When one considers this in conjunction with obvious examples of objective truths like

1. I exist,
2. 2 + 2 = 4,
3. If all men are mortal, and Socrates is a man, then he is mortal, and
4. It’s wrong to torture and rape a little girl for fun,

it’s hard to deny there are at least some objective truths. This is important because it means that there is an external reality with which we’re confronted. It is a certain way whether we think so or not, like it or not. What’s up for debate is not this reality’s presence but its scope and impact on our lives.