The Two Senses of 'Justification'
Traditionally knowledge has been defined as 'S knows p' when 1) p is true, 2) S believes p, and 3) S is justified in believing p. An important feature of the predominately externalist definition of knowledge is that the term 'justification' is eliminated. We can describe what 'knowledge' is, without using the word 'justification' at all. But why should we want to eliminate the word 'justification' from our definition of knowledge?

The major reason for eliminating the term is that it is ambiguous. As suggested by Mylan Engel, Jr. (1992), in ordinary discourse the word 'justified' is capable of being understood in more than one way. When speaking of justification, we can speak either about a person S being justified in holding a belief, or about a belief p being justified. The first sense is concerned with what it takes for a person to be justified in believing a proposition, and the second sense is concerned with whether a belief has the property of being justified from an external perspective.

The senses of 'personal justification' (PJ) and 'belief justification' (BJ) can be summarized as follows:

(Sense PJ) 'S is justified in believing p' if p is acquired as an immediate non-inferential belief, or S has reasonably (non-recklessly) acquired strong evidence and used good inferential reasoning for believing p.

(Sense BJ) 'p is a justified belief' if p is believed from inductive evidence (or abductive, deductive reasoning) that is relevant (i.e. truth-connecting, pertinent, non-defective) for why p should be believed true.

These senses of 'justification' are not metaphysical stipulations. This distinction reflects a real difference in the logical domains of discussion: persons and beliefs.

Sense PJ is about S, and S's possession of a set of evidential premises for believing p. Personal justification is where persons are judged, given their internal set of evidential premises. When evaluating whether a person is justified in believing p, we are asking whether they are warranted in believing p, given the evidence they possess. Normally, S is judged to be justified in believing p if S is diligent in assessing available evidence, and if satisfactory reasoning is used. Besides having inferences and arguments for beliefs, persons can also have basic non-inferential beliefs (e.g. perceptions) which can be personally justified based upon their immediate situation. This issue of being personally justified is a familiar Cartesian question.

Sense BJ is about p, and whether a belief has the property of being justified. Being truth-seekers, we wish to have beliefs based upon relevant, truth-connecting evidence for why p is true. If S believes p substantially upon factors that are false, or not relevant for why p should be believed, then S doesn't possess a justified belief. The possession of a justified belief implies that there are no defeating facts that render p false. Whether a belief is justified, is external to S's subjective conception of one's epistemic situation. This BJ sense is common to other externalist theories, such as reliabilism which maintain that justified beliefs have the property of being produced by reliable truth-conducive mechanisms. That justification can be external to S's ken is relatively new to Epistemology.

Michael Williams (2001) acknowledges Engel's distinction and observes: "We need to take account of two ways of understanding the phrase 'justified belief.' What exactly is supposed to be 'justified': a person's believing some particular proposition, or the proposition that he believes? There are two standpoints from which epistemic assessments of a person's belief can be made, corresponding to these two possibilities. Sometimes we focus on the person's entitlement to hold a certain view. But sometimes we are interested in whether the grounds on the basis of which he holds it are objectively adequate, whether they establish its truth, irrespective of whether he would be culpable for any defects" (pp. 21-22).

The PE definition recognizes both senses of justification. The distinction between a S posssesing a 'justified belief' as contrasted to S being 'personally justified' in believing p, is intuitive to most people. An easy illustration of these two senses is found with reference to an old-time American television detective program. As a detective and defense attorney, Perry Mason worked to uncover hidden evidence to possess a 'justified belief' about who the suspected actual wrongdoer is, in order to prove his client innocent. Mason works heroically to possess the right (truth-connecting) evidence. In a typical script, the (guilty) person is summoned to the stand and confesses under pressure of Mason's new evidence which ends the trial. Mason thus vindicates the innocent defendant, and prevents him/her from being found guilty upon the strong (but irrelevant) circumstantial evidence provided to the jury by the prosecuting attorney. Until the detective hero Mason appears, the jurors are 'personally justified' in believing the guilt of the accused innocent party.

With the PE definition of knowledge, the BJ sense of justification is implied by knowledge condition 3. Condition 3 asserts that S must possess a 'justified belief' as a condition for having knowledge. Condition 4a is a normative internalist condition that implies S should be 'personally justified' in believing p, as a condition for knowledge. While the PE definition is formulated to exclude the term 'justification,' it allows sense BJ to appear in condition 3 and sense PJ to appear in condition 4a.

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