To answer my title question, of course truth matters. But how and why does it matter? That’s what I want to examine.
In the previous post in this series, I already discussed photographs. As mentioned there, we do not question the truth of a photograph that we take ourselves. We might, however, question the truth of one that somebody gives us. The difference is that when we take the photograph ourselves, we know that the expected correspondence between reality and photographic representation was followed by virtue of us taking the photograph in the normal way and not doctoring the image.
What this suggests, is that truth is not needed by a solitary agent who is forming his own representations. This, roughly speaking, is why perception seems so reliable. Your pet cat or dog probably does not need to be concerned about truth. That is to say, truth is needed mainly for social discourse.
Here’s an example to illustrate the point. John wants to buy a window shade for his den. So he takes out a ruler and measures the window width as 90 inches, which he writes down on his notepad. As it happens, John was careless. He had picked up a meter ruler, and the width of the window was actually 90 cm. John now heads to the hardware store to purchase a shade. He takes that same ruler with him, and measures a shade of about the right width (what he calls 90 inches), and buys that. Returning home, the shade works out perfectly.
As we would normally describe it, the width John wrote down was not true. Nevertheless the shade fitted well. In writing down the width, John used a very non-standard correspondence between the world (the actual window width) and his representation. But, because he used that same non-standard correspondence when interpreting the representation, the shade that he purchased was a good fit.
What matters is consistency between the correspondence that is followed when forming a representation, and the correspondence that is used when interpreting that representation. As long as we maintain that consistency, there is no need for concern about truth.