This thesis is concerned with two kinds of 'singular' psychological phenomena. The first is the commonsense psychological explanation of action directed upon particular things and stuffs. The second is the nature of (visual) perceptual demonstrative thought. The two topics are brought together in an account of psychological explanation I call 'de re psychological explanation'. The primary aim of the thesis is to articulate and defend this account. The main thesis I seek to establish is that an adequate psychological explanation of an agent's action upon an object requires a relational or de re ascription of thought that (1) relates the agent to the object and (2) makes reference to a perceptual demonstrative mode of presentation of the object. This thesis is defended in two stages. In the first chapter I argue for the first half of the thesis, that relational ascriptions are necessary in any explanation of an action involving an object. In the fourth chapter I argue for the second half, that it is necessary that these relational ascriptions make reference to a perceptual demonstrative mode of presentation of the object acted on. The second half of the thesis involves the notion of a perceptual demonstrative mode of presentation. This necessitates an account of the nature of perceptual demonstrative thoughts, which is undertaken in chapters two and three. In the second chapter I explore two prominent theories of perceptual demonstrative thought. In the third chapter I sketch a new account 'property-dependent externalism' and argue that it is more adequate than the others. In chapter four, I return to de re explanation and develop it further into a covering-law account of psychological explanation. The rest of the thesis is given over to defending the elaborated covering-law account against two objections. I draw the claws of the first objection in the second half of the fourth chapter and answer the second objection in the final chapter.